MySQL error on Post - suspect subscription?

[hoochblues]

I keep getting the following MySQL error when I post a new thread. The thread posts ok. Based on the SQL statements, I am guessing I have a problem with subscriptions. But I am not sure where to look.

Any ideas?

Thanks!

Walt

PHP Code:

Database error in vBulletin 3.6.4:

Invalid SQL:

                SELECT email, username
                FROM user
                WHERE userid IN ();

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 ')' at line 3
Error Number : 1064
Date         : Friday, March 30th 2007 @ 01:47:45 PM