Database error in vBulletin 3.6.7

[bahattab]

hi
dose any one know why i am getting this errors and how to fix it :




Database error in vBulletin 3.6.7:

Invalid SQL:
SELECT COUNT(threadid) AS total FROM thread WHERE postuserid=;

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 : Saturday, June 23rd 2007 @ 05:18:01 PM
Script :
http://www.site.net/vb/external.php?...S2&forumids=96
Referrer :
IP Address : 86.60.67.86
Username : غير مسجل
Classname : vb_database