Database error in vBulletin 4.0.6:

Invalid SQL:

		  SELECT t.tagtext, p.tagtext as canonicaltagtext
			FROM tag t JOIN
				tag p ON t.canonicaltagid = p.tagid
			WHERE t.tagtext IN ('');

MySQL Error   : Unknown column 't.tagtext' in 'field list'
Error Number  : 1054
Request Date  : Monday, January 31st 2011 @ 08:09:15 PM
Error Date    : Monday, January 31st 2011 @ 08:09:15 PM
Script        : http://xxxx/newthread.php?do=postthread&f=102
Referrer      : http://xxxx/newthread.php?do=newthread&f=102&langid=14
IP Address    : 94.120.152.67
Username      : xxx
Classname     : vB_Database
MySQL Version : 5.0.91-community