If you have the forum installed in the root directory of the site (ie: not in a directory called 'forums'), what exactly should this line be in assistant.php:
$forumdir = "???"; // name of your forum directory
When I put nothing or a / only, the links inside the popup would go to the file, as in
http://search.php (without the URL) and would obviously be blank and not resolve.
Edit: (Version 2.2.9)