problem with admin index file

[Ninth Dimension]

Hi. I've just upgraded my forum from 3.5.3 to 3.6.8, it all appears to have worked as it should, but when I log into the admin section, the main panel on the right shows the following error message

Database error in vBulletin 3.6.8:

Invalid SQL:

	SELECT adminmessage.adminmessageid
	FROM vb3_adminmessage AS adminmessage
	INNER JOIN vb3_adminlog AS adminlog ON (adminlog.script = adminmessage.script AND adminlog.action = adminmessage.action)
	WHERE adminmessage.status = 'undone'
		AND adminmessage.script <> ''
		AND adminlog.dateline > adminmessage.dateline
	GROUP BY adminmessage.adminmessageid;

MySQL Error  : Illegal mix of collations (latin1_general_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation '='
Error Number : 1267
Date         : Saturday, August 18th 2007 @ 11:45:53 AM
Script       : http://arathor.net/admincp/index.php?do=home
Referrer     : http://arathor.net/admincp/index.php?do=nav
IP Address   : 86.134.211.171
Username     : Deus
Classname    : vb_database

Does anyone have any ideas on how to fix this? Thank you