Fix MySQL Error 2006

[Katmassive]

Database error in vBulletin 3.7.2:

Invalid SQL:
SELECT userid, joindate, options, username, opentag, closetag, posts 
    FROM vb_user as user 
    LEFT JOIN vb_usergroup as usergroup ON(user.usergroupid = usergroup.usergroupid) 
    WHERE joindate > 1231567200 ORDER BY username;

MySQL Error   : MySQL server has gone away
Error Number  : 2006
Request Date  : Saturday, January 10th 2009 @ 08:47:09 AM
Error Date    : Saturday, January 10th 2009 @ 08:47:11 AM

I'm guessing this is why the scheduled task to promote users isn't working... any suggestions