I figured out my mistake. I installed the plugin, created a menu http://www.domain/forums, but did not create a page with the forum’s name and shortcode. Once, everything worked.
Hope will help…
No it is not theme related. Just decided to install BBPress plugin on my website and get same criticall error. Unpublished every plugin, except BBPress and activated default theme 21. Same problem – critical error.Version 2.6.14
