[siriuxs]

I have the problem. When a user log-in in my forum, and after click on a someone thread, it appears the following errors:

Database error in vBulletin 3.5.2:
Invalid SQL:
SELECT dateline, userid FROM vb_customavatar WHERE userid =;
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 1 Error Number : 1064
Date : Wednesday, January 4th 2006 @ 11:00:37 AM
Script : http://www.mondoforum.org/forums/sho...st&threadid=56
Referrer : http://www.mondoforum.org/
IP Address : 87.6.36.123
Username :
Classname : vb_database

Why?