I'm getting the "500 internal server error" message at the last step of checkout. When I click on "Confirm order", it gives me the error above.

I'm using authorize.net (AIM) module. Turned CURL proxy to True, and put in the address, proxy.shr.secureserver.net:3128. Tested the CURL.php. It's all good. I don't know why it's doing this.

I'm so exhausted, can someone tell me what going on?

here's the website: http://www.jurnitea.com/store

here's the code for the checkout page:
HTML Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="en">
<head>
<title> : JURNI • Organic Tea Blossoms</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<meta name="keywords" content="Gift Certificates Teaware Gift Sets Tea tea, blossom, jasmine, green, white, china, brew " />
<meta name="description" content="JURNI :  - Gift Certificates Teaware Gift Sets Tea tea, blossom, jasmine, green, white, china, brew" />
<meta http-equiv="imagetoolbar" content="no" />
<meta name="author" content="The Zen Cart&trade; Team and others" />
<meta name="generator" content="shopping cart program by Zen Cart&trade;, [url]http://www.zen-cart.com[/url] eCommerce" />
<meta name="robots" content="noindex, nofollow" />

<base href="http://www.jurnitea.com/store/" />

<link rel="stylesheet" type="text/css" href="includes/templates/JurniTea/css/stylesheet.css" />
<link rel="stylesheet" type="text/css" href="includes/templates/JurniTea/css/stylesheet_css_buttons.css" />

<link rel="stylesheet" type="text/css" media="print" href="includes/templates/JurniTea/css/print_stylesheet.css" />
<script type="text/javascript" src="includes/templates/JurniTea/jscript/jscript_swfobject.js"></script>
<script language="javascript" type="text/javascript"><!--
var submitter = null;
function popupWindow(url) {
  window.open(url,'popupWindow','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,copyhistory=no,width=450,height=320,screenX=150,screenY=150,top=150,left=150')
}

function couponpopupWindow(url) {
  window.open(url,'couponpopupWindow','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,copyhistory=no,width=450,height=320,screenX=150,screenY=150,top=150,left=150')
}

function submitFunction($gv,$total) {
   if ($gv >=$total) {
     submitter = 1;	
   }
}

function submitonce(){
  if (document.checkout_confirmation.btn_submit) {
	  document.checkout_confirmation.btn_submit.disabled = true;
    setTimeout('button_timeout()', 4000);
    document.checkout_confirmation.submit();
  }
}

function button_timeout() {
  document.checkout_confirmation.submit.disabled = false;
}

//--></script>

</head>

<body id="checkoutconfirmationBody">

<div id="mainWrapper">


<table width="100&#37;" border="0" cellspacing="0" cellpadding="0" id="contentMainWrapper">
  <tr>

 <td id="navColumnOne" class="columnLeft" style="width: 200px">
<div class="upperLeftImageBox"><a href="index.php"><img src="./includes/templates/JurniTea/images/JurniLogo.gif" /></a></div>
<div class="cssnav">
<a href="index.php?main_page=page&id=15&chapter=1"><img src="./includes/templates/JurniTea/images/LeftNav.png" alt="View our amzing tea selection" /><span>about us</span></a>
</div> <div class="cssnav">
<a href="index.php?main_page=page&id=16&chapter=1"><img src="./includes/templates/JurniTea/images/LeftNav.png" alt="Learn more about JURNI Organic Teas" /><span>products</span></a>
</div> <div class="cssnav">
<a href="index.php?main_page=page&id=17&chapter=1"><img src="./includes/templates/JurniTea/images/LeftNav.png" alt="See our upcoming events" /><span>wholesale</span></a>
</div> <div class="cssnav">
<a href="index.php?main_page=contact_us"><img src="./includes/templates/JurniTea/images/LeftNav.png" alt="Contact JURNI Tea" /><span>contact</span></a>

</div>
<img src="./includes/templates/JurniTea/images/TeaBalls.gif">

<div id="navColumnOneWrapper" style="width: 150px"></div></td>
    <td valign="top"><!--bof-header logo and navigation display-->
</div>
<br class="clearBoth" />
<!--eof-branding display-->

<!--eof-header logo and navigation display-->
<!-- bof  breadcrumb -->
    <div id="navBreadCrumb">  <a href="http://www.jurnitea.com/store/">Home</a>&nbsp;::&nbsp;

  <a href="http://www.jurnitea.com/store/index.php?main_page=checkout_shipping">Checkout</a>&nbsp;::&nbsp;
Confirmation
</div>
<!-- eof breadcrumb -->
<!--bof-optional categories tabs navigation display-->
<div id="navCatTabsWrapper">
<div id="navCatTabs">
<ul>
  <li><a class="category-top" href="http://www.jurnitea.com/store/index.php?main_page=index&amp;cPath=65">Tea</a> </li>
  <li><a class="category-top" href="http://www.jurnitea.com/store/index.php?main_page=index&amp;cPath=68">Teaware</a> </li>

  <li><a class="category-top" href="http://www.jurnitea.com/store/index.php?main_page=index&amp;cPath=69">Gift Sets</a> </li>
  <li><a class="category-top" href="http://www.jurnitea.com/store/index.php?main_page=index&amp;cPath=21">Gift Certificates</a> </li>
</ul>
</div>
</div>
<!--eof-optional categories tabs navigation display-->




<!-- bof upload alerts -->

<!-- eof upload alerts -->

<div class="centerColumn" id="checkoutConfirmDefault">

<h1 id="checkoutConfirmDefaultHeading"></h1>


<div id="checkoutBillto" class="back">
<h2 id="checkoutConfirmDefaultBillingAddress">Billing/Payment Information</h2>
<div class="buttonRow forward"><a href="http://www.jurnitea.com/store/index.php?main_page=checkout_payment"><img src="includes/templates/template_default/buttons/english/small_edit.gif" alt="Edit" title=" Edit " width="40" height="16" /></a></div>

<address>Armen Ohannesian<br /> 16046 Malden Street<br /> North Hills, CA    91343<br /> United States</address>


<h3 id="checkoutConfirmDefaultPayment">Payment Method:</h3> 
<h4 id="checkoutConfirmDefaultPaymentTitle">Credit Card</h4>

<div class="important"></div>
<div class="important">
<div class="back">Credit Card Type:</div>
<div >Visa</div>
<div class="back">Credit Card Owner:</div>
<div >Armen Ohannesian</div>

<div class="back">Credit Card Number:</div>
<div >40######XXXX0027</div>
<div class="back">Credit Card Expiry Date:</div>
<div >January, 2010</div>
<div class="back">CVV Number:</div>
<div >213</div>
      </div>

<br class="clearBoth" />
</div>

<br class="clearBoth" />
<hr />

<h2 id="checkoutConfirmDefaultHeadingComments">Special Instructions or Order Comments</h2>
<div class="buttonRow forward"><a href="http://www.jurnitea.com/store/index.php?main_page=checkout_payment"><img src="includes/templates/template_default/buttons/english/small_edit.gif" alt="Edit" title=" Edit " width="40" height="16" /></a></div>
<div>None</div>
<br class="clearBoth" />
<hr />

<h2 id="checkoutConfirmDefaultHeadingCart">Shopping Cart Contents</h2>

<div class="buttonRow forward"><a href="http://www.jurnitea.com/store/index.php?main_page=shopping_cart"><img src="includes/templates/template_default/buttons/english/small_edit.gif" alt="Edit" title=" Edit " width="40" height="16" /></a></div>
<br class="clearBoth" />



      <table border="0" width="100%" cellspacing="0" cellpadding="0" id="cartContentsDisplay">
        <tr class="cartTableHeading">
        <th scope="col" id="ccQuantityHeading" width="30">Qty.</th>
        <th scope="col" id="ccProductsHeading">Item Name</th>
          <th scope="col" id="ccTotalHeading">Total</th>
        </tr>

        <tr class="rowEven">
          <td  class="cartQuantity">1&nbsp;x</td>
          <td class="cartProductDisplay">Gift Certificates          
<ul class="cartAttribsList">      <li>Amount: $100.00</li>
</ul>        </td>

        <td class="cartTotalDisplay">
          $100.00        </td>

      </tr>
      </table>
      <hr />

<div id="orderTotals"><div id="otsubtotal">
    <div class="totalBox larger forward">$100.00</div>
    <div class="lineTitle larger forward">Sub-Total:</div>
</div>
<br class="clearBoth" />
<div id="otshipping">

    <div class="totalBox larger forward">$0.00</div>
    <div class="lineTitle larger forward">Free Shipping:</div>
</div>
<br class="clearBoth" />
<div id="otgrouppricing">
    <div class="totalBox larger forward">-$10.00</div>
    <div class="lineTitle larger forward">Group Discount:</div>
</div>
<br class="clearBoth" />

<div id="ottotal">
    <div class="totalBox larger forward">$90.00</div>
    <div class="lineTitle larger forward">Total:</div>
</div>
<br class="clearBoth" />
</div>

<form name="checkout_confirmation" action="http://www.jurnitea.com/store/index.php?main_page=checkout_process" method="post" id="checkout_confirmation" onsubmit="submitonce();"><input type="hidden" name="cc_owner" value="Armen Ohannesian" /><input type="hidden" name="cc_expires" value="0110" /><input type="hidden" name="cc_type" value="Visa" /><input type="hidden" name="cc_number" value="4007000000027" /><input type="hidden" name="cc_cvv" value="213" /><input type="hidden" name="zenid" value="7aa43bf361eeecfed67065bda9d91443" /><div class="buttonRow forward"><input type="image" src="includes/templates/template_default/buttons/english/button_confirm_order.gif" alt="Confirm Order" title=" Confirm Order " name="btn_submit" id="btn_submit" /></div>
</form>
<div class="buttonRow back"><strong>Final Step</strong><br />- continue to confirm your order. Thank you!</div>

</div>
</td>

<td id="navColumnTwo" class="columnRight" style="width: 200px">
<!-- <img src="./includes/templates/JurniTea/images/cupOfTea2.gif"> -->

  <div id="flashcontent">
  To see our blossom tea in action, please download the latest Flash Player.
</div>
  <script type="text/javascript">
   var so = new SWFObject("./includes/templates/JurniTea/images/cupOfTea.swf", "Blossom Tea", "200", "30", "8", "b2a476");
   //so.setAttribute('xiRedirectUrl', 'http://www.jurnitea.com/'); <br>
	// must be the absolute URL to your site
   so.write("flashcontent");
</script>
  <div id="navColumnTwoWrapper" style="width: 170px"><!--// bof: loginbox //-->
<div class="rightBoxContainer" id="loginbox" style="width: 170px">

<h3 class="rightBoxHeading" id="loginboxHeading">My Account</h3>
<!--testloginbox--><div id="loginboxContent" class="sideBoxContent"><ul><li><a class="loginBoxLinks" href="http://www.jurnitea.com/store/index.php?main_page=account">My Account</a></li><li><a class="loginBoxLinks" href="http://www.jurnitea.com/store/index.php?main_page=shopping_cart">Shopping Cart</a></li><li><a class="loginBoxLinks" href="http://www.jurnitea.com/store/index.php?main_page=logoff">Log off</a></li></ul></div></div>
<!--// eof: loginbox //-->

<!--// bof: search //-->
<div class="rightBoxContainer" id="search" style="width: 170px">
<h3 class="rightBoxHeading" id="searchHeading"><label>Search</label></h3>
<div id="searchContent" class="sideBoxContent centeredContent"><form name="quick_find" action="http://www.jurnitea.com/store/index.php?main_page=advanced_search_result" method="get"><input type="hidden" name="main_page" value="advanced_search_result" /><input type="hidden" name="search_in_description" value="1" /><input type="text" name="keyword" size="18" maxlength="100" style="width: 140px" value="Enter search keywords here" onfocus="if (this.value == 'Enter search keywords here') this.value = '';" onblur="if (this.value == '') this.value = 'Enter search keywords here';" /><br /><input type="submit" value="Search" style="width: 50px" /><br /><a href="http://www.jurnitea.com/store/index.php?main_page=advanced_search">Advanced Search</a></form></div></div>
<!--// eof: search //-->

<!--// bof: shoppingcart //-->

<div class="rightBoxContainer" id="shoppingcart" style="width: 170px">
<h3 class="rightBoxHeading" id="shoppingcartHeading"><a href="http://www.jurnitea.com/store/index.php?main_page=shopping_cart">Shopping Cart&nbsp;&nbsp;[more]</a></h3>
<div id="shoppingcartContent" class="sideBoxContent"><div id="cartBoxListWrapper">
<ul>
<li><span class="cartOldItem">1ea.-&nbsp;</span><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=47:c04263f81470ddd1f922b84b3179288b"><span class="cartOldItem">Gift Certificates</span></a></li>
</ul>
</div><hr /><div class="cartBoxTotal">$100.00</div><br class="clearBoth" /></div></div>
<!--// eof: shoppingcart //-->

<!--// bof: orderhistory //-->
<div class="rightBoxContainer" id="orderhistory" style="width: 170px">
<h3 class="rightBoxHeading" id="orderhistoryHeading">Quick Re-Order</h3>

<div id="orderhistoryContent" class="sideBoxContent">
<ul class="orderHistList">
<li><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=180">Blushing Beauty</a>&nbsp;&nbsp;<a href="http://www.jurnitea.com/store/index.php?main_page=index.php&amp;action=cust_order&amp;pid=180"><img src="includes/templates/template_default/images/icons/cart.gif" alt="Add this product to your cart by clicking here." title=" Add this product to your cart by clicking here. " width="16" height="17" /></a></li>
<li><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=47">Gift Certificates</a>&nbsp;&nbsp;<a href="http://www.jurnitea.com/store/index.php?main_page=index.php&amp;action=cust_order&amp;pid=47"><img src="includes/templates/template_default/images/icons/cart.gif" alt="Add this product to your cart by clicking here." title=" Add this product to your cart by clicking here. " width="16" height="17" /></a></li>
<li><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=195">Marakesh Mint</a>&nbsp;&nbsp;<a href="http://www.jurnitea.com/store/index.php?main_page=index.php&amp;action=cust_order&amp;pid=195"><img src="includes/templates/template_default/images/icons/cart.gif" alt="Add this product to your cart by clicking here." title=" Add this product to your cart by clicking here. " width="16" height="17" /></a></li>
<li><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=194">Secret Fortune</a>&nbsp;&nbsp;<a href="http://www.jurnitea.com/store/index.php?main_page=index.php&amp;action=cust_order&amp;pid=194"><img src="includes/templates/template_default/images/icons/cart.gif" alt="Add this product to your cart by clicking here." title=" Add this product to your cart by clicking here. " width="16" height="17" /></a></li>
<li><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=181">Shanghai</a>&nbsp;&nbsp;<a href="http://www.jurnitea.com/store/index.php?main_page=index.php&amp;action=cust_order&amp;pid=181"><img src="includes/templates/template_default/images/icons/cart.gif" alt="Add this product to your cart by clicking here." title=" Add this product to your cart by clicking here. " width="16" height="17" /></a></li>
<li><a href="http://www.jurnitea.com/store/index.php?main_page=product_info&amp;products_id=190">Sunset Glory</a>&nbsp;&nbsp;<a href="http://www.jurnitea.com/store/index.php?main_page=index.php&amp;action=cust_order&amp;pid=190"><img src="includes/templates/template_default/images/icons/cart.gif" alt="Add this product to your cart by clicking here." title=" Add this product to your cart by clicking here. " width="16" height="17" /></a></li>
</ul>
</div></div>
<!--// eof: orderhistory //-->

<!--// bof: ccaccept //-->
<div class="rightBoxContainer" id="ccaccept" style="width: 170px">
<h3 class="rightBoxHeading" id="ccacceptHeading">We Accept ...</h3>
<div id="ccacceptContent" class="sideBoxContent">
</center></div>
<center>
<img id="ccVisa" class="cc_img" src="images/cc_logos/logo_ccVisa.gif" />
<img id="ccAmex" class="cc_img" src="images/cc_logos/logo_ccAmex.gif" />
<img id="ccMC" class="cc_img" src="images/cc_logos/logo_ccMC.gif" />
<div id="ccacceptContent" class="sideBoxContent">
</center></div>
</div>
<!--// eof: ccaccept //-->

</div></td>

  </tr>
</table>



<!--bof-navigation display -->
<div id="navSuppWrapper">
<div id="navSupp">
<ul>
<li><a href="http://www.jurnitea.com/store/">Home</a></li>
<li>&nbsp;::&nbsp;
  <a href="http://www.jurnitea.com/store/index.php?main_page=account">My Account</a>

&nbsp;::&nbsp;
  <a href="http://www.jurnitea.com/store/index.php?main_page=privacy">Privacy Notice</a>
</li>
</ul>
</div>
</div>
<!--eof-navigation display -->

<!--bof-ip address display -->
<!--eof-ip address display -->

<!--bof-banner #5 display -->
<!--eof-banner #5 display -->

<!--bof- site copyright display -->
<div id="siteinfoLegal" class="legalCopyright">Copyright &copy; 2007 Jurni Tea. Powered by <a href="http://www.zen-cart.com" target="_blank">Zen Cart</a></div>
<!--eof- site copyright display -->

</div>
<!--bof- parse time display -->
<!--eof- parse time display -->
<!--bof- banner #6 display -->
<!--eof- banner #6 display -->

</body></html>