database error :( please help

[madness85]

Hi all here?s what I?m trying to do I have created a usergroup that is for questioning before banned. This usergroup has only permissions to view a pacific hidden section the rest of the forum permissions are set to no. this was working fine for many months now I found that any user on this usergroup receives DB error.

Database error in vBulletin 4.2.0:

Invalid SQL:

SELECT u.username,u.userid,t.title,t.threadid
FROM thread AS t
LEFT JOIN user AS u ON (t.postuserid=u.userid)
WHERE forumid IN()
ORDER BY dateline DESC
LIMIT 10;

MySQL Error : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')
ORDER BY dateline DESC
LIMIT 10' at line 4

I've already made a post on vb.com and been asked to disable all hooks and I've tried disabling plugins. I hope some can help me here

Error Number : 1064