Column layout (all messed up) AND template width issues

Hi! I'm new to posting but I've searched the forums without much luck for my particular problem. I am using version 1.3.8. The example page in my shop is here:
http://www.twigsandhoney.com/catalog/index.php?main_page=index&cPath=1_17
I installed the column layout addon. I am trying to have product listings in 3 neat columns. I have selected this in admin/product listing/layout style AND I chose 3 columns per row. In the link above, you can see that it is sporadic. Some rows have two columns and others have one. I read this thread with a similar problem:
http://www.zen-cart.com/forum/showthread.php?t=41025
I tried to adjust the mainwrapper in my style sheet and it looks like this:

/wrappers - page or section containers/
#mainWrapper {
background-color: #ffffff;
text-align: left;
vertical-align: top;
border: 1px solid #9a9a9a;
width: 1000px;
}

I have fiddled with this (which is my custom template) by changing the width to 750px, 1000px, 100%.... and nothing I do seems to change the width of my template (assuming that the size of the template is causing the columns to get all out of order).

Am I completely off base? Should I be looking for the fix in some other place? Any help would be greatly appreciated! I've been working on this for hours today and earlier this week.

I'm not sure if it matters, but I wanted to add that this is what my tpl_header looks like:

<!--bof-navigation display--> <div id="navMainWrapper"> <div id="navMain"> <ul class="back"> <li><?php echo '<a href="' . HTTP_SERVER . DIR_WS_CATALOG . '">'; ?><?php echo HEADER_TITLE_CATALOG; ?></a></li> <?php if ($_SESSION['customer_id']) { ?> <li><a href="<?php echo zen_href_link(FILENAME_LOGOFF, '', 'SSL'); ?>"><?php echo HEADER_TITLE_LOGOFF; ?></a></li> <li><a href="<?php echo zen_href_link(FILENAME_ACCOUNT, '', 'SSL'); ?>"><?php echo HEADER_TITLE_MY_ACCOUNT; ?></a></li> <?php } else { if (STORE_STATUS == '0') { ?> <li><a href="<?php echo zen_href_link(FILENAME_LOGIN, '', 'SSL'); ?>"><?php echo HEADER_TITLE_LOGIN; ?></a></li> <?php } } ?> <?php if ($_SESSION['cart']->count_contents() != 0) { ?>

<li><a href="<?php echo zen_href_link(FILENAME_SHOPPING_CART, '', 'NONSSL'); ?>"><?php echo HEADER_TITLE_CART_CONTENTS; ?></a></li>
<li><a href="<?php echo zen_href_link(FILENAME_CHECKOUT_SHIPPING, '', 'SSL'); ?>"><?php echo HEADER_TITLE_CHECKOUT; ?></a></li>

<?php }?> </ul> </div> <div id="navMainSearch"><?php require(DIR_WS_MODULES . 'sideboxes/search_header.php'); ?></div> <br class="clearBoth" /> </div> <!--eof-navigation display--> <!--bof-header logo and navigation display--> <?php if (!isset($flag_disable_header) || !$flag_disable_header) { ?> <div id="headerWrapper"> <!--bof-navigation display--> <!--bof-branding display--> <div id="logoWrapper"> <div id="logo"><?php echo '<a href="' . HTTP_SERVER . DIR_WS_CATALOG . '">' . zen_image($template->get_template_dir(HEADER_LOGO_IMAGE, DIR_WS_TEMPLATE,

$current_page_base,'images'). '/' . HEADER_LOGO_IMAGE, HEADER_ALT_TEXT) . '</a>'; ?></div>

<?php if (HEADER_SALES_TEXT != '' || (SHOW_BANNERS_GROUP_SET2 != '' && $banner = zen_banner_exists('dynamic', SHOW_BANNERS_GROUP_SET2))) { ?>

<div id="taglineWrapper">

<?php if (HEADER_SALES_TEXT != '') { ?>

  <div id="tagline"><?php echo HEADER_SALES_TEXT;?></div>

<?php } ?> <?php if (SHOW_BANNERS_GROUP_SET2 != '' && $banner = zen_banner_exists('dynamic', SHOW_BANNERS_GROUP_SET2)) { if ($banner->RecordCount() > 0) { ?>

  <div id="bannerTwo" class="banners"><?php echo zen_display_banner('static', $banner);?></div>

<?php } } ?>

</div>

<?php } // no HEADER_SALES_TEXT or SHOW_BANNERS_GROUP_SET2 ?> </div> <br class="clearBoth" /> <!--eof-branding display--> <!--eof-header logo and navigation display--> <!--bof-optional categories tabs navigation display--> <?php require($template->get_template_dir('tpl_modules_categories_tabs.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_categories_tabs.php'); ?> <!--eof-optional categories tabs navigation display-->