try changing:
// WebAssist iRite: Rich Text Editor for Dreamweaver
$WARichTextEditor_1 = CreateRichTextEditor ("ContentValue", "../../WA_iRite/", "713px", "400px", "Custom", "../custom/contents_insert_ContentValue1.js", (isset($_POST['ContentValue']) ? $_POST['ContentValue'] : "" ) );
to:
// WebAssist iRite: Rich Text Editor for Dreamweaver
$WARichTextEditor_1 = CreateRichTextEditor ("ContentValue", "../WA_iRite/", "713px", "400px", "Custom", "../custom/contents_insert_ContentValue1.js", "".(isset($_POST['ContentValue']))?$_POST['ContentValue']:("") ."");
any time you are getting a white screen, there is ussually a PHP error occuring. Add the following at line of the page to see the error:
<?php
error_reporting(E_ALL);
ini_set('display_errors','on');
?>