Reply To: Public capabilities on custom post type
Are you sure it’s just a bbpress issue?
The ‘lastest’ bbpress is quite old now, so if it was an issue, I’m sure it would have been flagged by now.
presume you have
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, as a test switch to a default theme such as twentytwelve, and see if this fixes.