Re: Moderator New Post Notification error?
Have you tried disabling the plugin to see if the problem persists?
Do you actually have a table called bb_users in the forums database, or are you using the wp_users table and an integrated installation?
Also, I see that plugin says compatible up to 0.8.3. If you’re using the latest 0.9.0.2, you might want to post your issue on that plugin page or try to contact the plugin author.
Or maybe read through the comments on that plugin page and see how others resolved the same problem.