Forum forum links not working
 

I upgraded from 3.6.5 to 4.0.4. Every thing looks and acts alright except the links to forums. The old data base was imported and converted to the 4.0.4 version. I have all the members and all the posts and threads.

When go on my forums page and try to get inside a forum category i get an error stating

"Invalid Forum specified. If you followed a valid link, please notify the administrator"

The same thing is when i'm on a thread page and try to get to the category that contains the thread by accessing the tree link just underneath navbar.

On version 3.6.5 i was using vbseo 3.1.0 but i disabled it before upgrading.

Does anyone know what might be the problem ?