vBulletin Error - Help! :o

[Markro]

I'm not sure the cause of this error, does anyone know or has anyone seen it before?

Database error in vBulletin 3.7.2:

Invalid SQL:

               SELECT *
               FROM threadrate
               WHERE userid = 18508
                       AND threadid =;

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 4
Error Number  : 1064
Request Date  : Thursday, November 6th 2008 @ 02:03:02 AM
Error Date    : Thursday, November 6th 2008 @ 02:03:02 AM
Script        : http://www.domain.com/showthread.php?
Referrer      :
IP Address    : xx.xx.xx.xx.xx
Username      : User_name
Classname     : vB_Database
MySQL Version :

Thanks, Mark