[EWGF]

I'm testing vbcredits on a testforum and since I upgraded the testforum to 3.6.8, I've received via email the following message a couple of times. Vbcredits itself seem to be running fine. Since the word 'credits' is mentioned a couple of times, I'm posting this here.

Database error in vBulletin 3.6.8:

Invalid SQL: SELECT user.userid, user.usergroupid, user.credits_numrefs, user.referrerid, user.reputation, user.posts, user.joindate, user.credits_canget, ref.credits_numrefs AS refnumrefs, ref.usergroupid AS refugid, ref.credits_canget AS cangetref FROM user AS user LEFT JOIN user AS ref ON (ref.userid = user.referrerid) WHERE (user.referrerid != 0 AND user.joindate > );

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 : Sunday, July 29th 2007 @ 03:12:13 PM
Script : http://**********/testforum/cron.php?&rand=543503
Referrer : http://**********/testforum/member.php?u=1
IP Address : 212.83.93.**
Username : Unregistered
Classname : vB_Database

Is there a conflict between my 3.6.8 testforum and vbcredits or is it something else?