Ovidiu, I know you had similar problem. I've already posted it on author's page and at wpmu.org but I'm in a hurry and need this fast.
So, If using drop down menus like this one http://www.studiograsshopper.ch/admin-drop-down-menus-wp-25/ users can’t reach Help Desk's admin pages. Error shows up. Like this:
Not Found
The requested URL /wp-admin/help-desk.php was not found on this server.
Apache/2.2.3 (CentOS) Server at subdomain.domain.com Port 80
Any idea on how to solve this?