Re: get some trouble …
I think you will be redirected from bb-admin if you’re not logged in or if you’re logged in as someone other than keymaster. Can you take a screenshot showing who you’re logged in as?
Sounds like you don’t have a link to Admin either. That makes me think you’re not the keymaster. Can you confirm with direct access to the database that you are in fact the key master? I think that’s the source of your problem.
There was also a plugin that I thought could do this. Are you using any plugins? I would tell you to disable them one by one, but since you can’t access the admin section, that would be hard. I think right now you are going to need direct access to your database tables with a tool like phpMyAdmin or whatever your host provides.
Regarding the WordPress error, that’s a WordPress issue and I think you will find help over at the WordPress forums, for example:
(From the looks of it, there is no more post2cat table in WP 2.3, but not all the plugins have caught up, so some of them are causing this error. Or possibly you just need to upgrade the database schema to match your WordPress installation? In either case, that’s a WordPress issue and totally unrelated to bbPress.)