Are you hosting on IIS or apache?
Try adding the following at line 1 of the page you have applied HTML editor to:
<?php $_SERVER['REQUEST_URI'] = substr($_SERVER['PHP_SELF'],0); ?>
PHP Version 5.2.12
IIS 6
Sorry, don't understand "page you have applied HTML editor to"
The intent here is to edit an image, do you mean the page the image is in?