[@robin-w Moderator 12 years, 3 months ago]

As @pinkishhue suggests, try

Plugins

Deactivate all but bbpress and see if this fixes. if it does, re-enable one at a time to see which is causing the error.

Themes

If plugins don’t pinpoint the problem, switch to a default theme such as twentytwelve, and see if this fixes.

this should get you to a working platform from which you can work out where the issue lies.