Is seems like BB doesn't play too well with either the qtranslate or the DMSGuestbook plugins:
Just on one of our sites it is impossible to log in if BB is activated. As soon as I delete it (via ftp), I get in as normal.
I get this error message:
We're sorry, but we could not fulfill your request for /wp-login.php on this server.
You do not have permission to access this server. Data may not be posted from offsite forms.
Your technical support key is: 6dbd-b160-cd36-xxxx
You can use this key to fix this problem yourself.
If you are unable to fix the problem yourself, please contact etc
Now, after turning those other plugins off and then on again one by one, it first seemed like everything was fine. Then, a little later, the problem is back.
Using BB 2.0.43 with WP 3.1.3