Code:
<?php
/**
 * @package languageDefines
 * @copyright Copyright 2003-2006 Zen Cart Development Team
 * @copyright Portions Copyright 2003 osCommerce
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id: button_names.php 5410 2006-12-27 03:56:46Z drbyte $
 */


/**
 * define the button images used in the project
 */

define('BUTTON_IMAGE_ADD_TO_CART', 'addtocart-button.jpg');
define('BUTTON_IMAGE_ADD_ADDRESS', 'addaddress-button.jpg');
define('BUTTON_IMAGE_ADD_PRODUCTS_TO_CART','addtocart-button.jpg');
define('BUTTON_IMAGE_BACK', 'backarrow_icon.gif');
define('BUTTON_IMAGE_BUY_NOW', buynow-button.jpg');
define('BUTTON_IMAGE_CANCEL', 'cancel-button.jpg');
define('BUTTON_IMAGE_CHANGE_ADDRESS', 'changeaddress-button.jpg');
define('BUTTON_IMAGE_CHECKOUT', 'checkout-button.jpg');
define('BUTTON_IMAGE_CONFIRM_SEND', 'confirm-button.jpg');
define('BUTTON_IMAGE_CONFIRM_ORDER', 'confirm-button.jpg');
define('BUTTON_IMAGE_CONTINUE', 'continue-button.jpg');
define('BUTTON_IMAGE_CONTINUE_SHOPPING', 'continueshopping-button.jpg');
define('BUTTON_IMAGE_DELETE', 'delete-button.jpg');
define('BUTTON_IMAGE_DELETE_SMALL', 'deletesmall-button.jpg');
define('BUTTON_IMAGE_DOWNLOAD', 'download-button.jpg');
define('BUTTON_IMAGE_EDIT_SMALL', 'editsmall-button.jpg');
define('BUTTON_IMAGE_IN_CART', 'incart-button.jpg');
define('BUTTON_IMAGE_LOGIN', 'login-button.jpg');
define('BUTTON_IMAGE_NEXT', 'next-button.gif');
define('BUTTON_IMAGE_PREVIOUS', 'backarrow_icon.gif');
define('BUTTON_IMAGE_REDEEM', 'redeem-button.jpg');
define('BUTTON_IMAGE_RETURN_TO_PROD_LIST', 'returnlist-button.jpg');
define('BUTTON_IMAGE_REVIEWS', 'review-button.jpg');
define('BUTTON_IMAGE_SEARCH', 'search-button.jpg');
define('BUTTON_IMAGE_SEND', 'send-button.jpg');
define('BUTTON_IMAGE_SEND_A_GIFT_CERT', 'sendgiftcertificate-button.jpg');
define('BUTTON_IMAGE_SEND_ANOTHER', 'sendanother-button.jpg');
define('BUTTON_IMAGE_SHIPPING_ESTIMATOR', 'shippingestimator-button.jpg');
define('BUTTON_IMAGE_SOLD_OUT','soldout-button.jpg');
define('BUTTON_IMAGE_SOLD_OUT_SMALL','soldout-button.jpg');
define('BUTTON_IMAGE_SUBMIT', 'submit-button.jpg');
define('BUTTON_IMAGE_TELL_A_FRIEND', 'tellafriend-button.jpg');
define('BUTTON_IMAGE_TELLAFRIEND', 'tellafriend-button.jpg');
define('BUTTON_IMAGE_UNSUBSCRIBE', 'unsubscribe-button.jpg');
define('BUTTON_IMAGE_UPDATE', 'update-button.jpg');
define('BUTTON_IMAGE_VIEW_SMALL', 'view-button.jpg');
define('BUTTON_IMAGE_WRITE_REVIEW', 'writereview-button.jpg');
define('BUTTON_IMAGE_READ_REVIEWS', 'readreview-button.jpg');
define('BUTTON_IMAGE_GOTO_PROD_DETAILS', 'productdetails-button.jpg');
define('BUTTON_IMAGE_MORE_REVIEWS', 'morereviews-button.jpg');
define('BUTTON_IMAGE_CONTINUE_CHECKOUT', 'continuecheckout-button.jpg');
//define('PREVNEXT_BUTTON_NEXT', '[Next&nbsp;&gt;&gt;]');
//define('PREVNEXT_BUTTON_LAST', 'LAST&gt;&gt;');


define('BUTTON_IMAGE_CREATE_ACCOUNT', 'createaccount-button.jpg');
define('BUTTON_IMAGE_LOG_OFF', 'logout-button.jpg');
/*
 * ALT tags used for buttons
 */
 
define('BUTTON_CREATE_ACCOUNT_ALT', 'Sign Up');
define('BUTTON_LOG_OFF_ALT', 'Log Off');
define('BUTTON_ADD_TO_CART_ALT', 'Add This to My Cart');
define('BUTTON_ADD_ADDRESS_ALT', 'Add Address');
define('BUTTON_ADD_PRODUCTS_TO_CART_ALT','Add Selected Products to Cart');
define('BUTTON_BACK_ALT', 'Back');
define('BUTTON_BUY_NOW_ALT', 'Buy Now');
define('BUTTON_CANCEL_ALT', 'Cancel');
define('BUTTON_CHANGE_ADDRESS_ALT', 'Change Address');
define('BUTTON_CHECKOUT_ALT', 'Checkout');
define('BUTTON_CONFIRM_SEND_ALT', 'Send Gift Certificate');
define('BUTTON_CONFIRM_ORDER_ALT', 'Confirm Order');
define('BUTTON_CONTINUE_ALT', 'Continue');
define('BUTTON_CONTINUE_SHOPPING_ALT', 'Continue Shopping');
define('BUTTON_DELETE_ALT', 'Delete');
define('BUTTON_DELETE_SMALL_ALT', 'Delete');
define('BUTTON_DOWNLOAD_ALT', 'Download Now');
define('BUTTON_EDIT_SMALL_ALT', 'Edit');
define('BUTTON_IN_CART_ALT', 'Add to Cart');
define('BUTTON_LOGIN_ALT', 'Sign In');
define('BUTTON_NEXT_ALT', 'Next');
define('BUTTON_PREVIOUS_ALT', 'Previous');
define('BUTTON_REDEEM_ALT', 'Redeem');
define('BUTTON_RETURN_TO_PROD_LIST_ALT', 'Return to the Product List');
define('BUTTON_REVIEWS_ALT', 'Go to the Reviews Page');
define('BUTTON_SEARCH_ALT', 'Search');
define('BUTTON_SEND_ALT', 'Send Now');
define('BUTTON_SEND_ANOTHER_ALT', 'Send Another Gift Certificate');
define('BUTTON_SEND_A_GIFT_CERT_ALT', 'Send A Gift Certificate');
define('BUTTON_SHIPPING_ESTIMATOR_ALT', 'Shipping Estimator');
define('BUTTON_SOLD_OUT_ALT', 'Sold Out');
define('BUTTON_SOLD_OUT_SMALL_ALT', 'Sold Out');
define('BUTTON_SUBMIT_ALT', 'Submit the Information');
define('BUTTON_TELL_A_FRIEND_ALT', 'Tell a Friend');
define('BUTTON_TELLAFRIEND_ALT', 'Tell a Friend');
define('BUTTON_UNSUBSCRIBE', 'Unsubscribe');
define('BUTTON_UPDATE_ALT', 'Update');
define('BUTTON_VIEW_SMALL_ALT', 'View');
define('BUTTON_WRITE_REVIEW_ALT', 'Write Review');
define('BUTTON_READ_REVIEWS_ALT', 'Read the Review');
define('BUTTON_GOTO_PROD_DETAILS_ALT', 'Go To This Product\'s Detailed Information');
define('BUTTON_MORE_REVIEWS_ALT', 'Read More Reviews');
?>
I did that and it didn't work, so I wrote this over the original buttons.php and that made the screen go blank every time it loads. So I reloaded the original file and then it worked again. What is wrong now?