Os gwelwch yn dda gwirio logiau hwn

Code:
Database error in vBulletin 4.2.1:

Invalid SQL:
UPDATE vb_user SET usergroupid = 2 WHERE usergroupid 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 1
Error Number  : 1064
Request Date  : Friday, October 18th 2013 @ 12:04:46 AM
Error Date    : Friday, October 18th 2013 @ 12:04:46 AM
Script        : ****//***/community/admincp/plugin.php?do=productkill
Referrer      : ***://***/community/admincp/plugin.php?do=productdelete&productid=vbenterprisetranslator&s=
IP Address    : ***
Username      : murdercode
Classname     : vB_Database_MySQLi
MySQL Version : 5.5.****
sut i ddatrys?