SQL error.. Help plz!!

[SpaMMerGR]

I moved from phpbb to vb 3.6.9, Search was working normally, i did some usergroup changes (username color, bold) and now everytime i search or click on "get new posts" get this db error:

Database error in vBulletin 3.6.9:

Invalid SQL:

			SELECT post.pagetext AS preview,
				thread.threadid, thread.threadid AS postid, thread.title AS threadtitle, thread.iconid AS threadiconid, thread.dateline, thread.forumid,
				thread.replycount, IF(thread.views=0, thread.replycount+1, thread.views) as views, thread.sticky,
				thread.pollid, thread.open, thread.lastpost AS postdateline, thread.visible, thread.hiddencount, thread.deletedcount,
				thread.lastpost, thread.lastposter, thread.lastpostid, thread.attach, thread.postusername, thread.forumid,


				deletionlog.userid AS del_userid, deletionlog.username AS del_username, deletionlog.reason AS del_reason,

				user.userid AS postuserid
				
				
				, attachment.thumbnail_filesize AS thumbsize , MIN(attachment.attachmentid) AS attachmentid , post.pagetext AS previewbbcode
			FROM thread AS thread
			LEFT JOIN user AS user ON(user.userid = thread.postuserid)

			LEFT JOIN deletionlog AS deletionlog ON(thread.threadid = deletionlog.primaryid AND deletionlog.type = 'thread')
			
			
			LEFT JOIN post AS post ON(post.postid = thread.firstpostid)
			
			LEFT JOIN attachment as attachment ON(attachment.postid = thread.firstpostid AND (attachment.extension = 'jpg' OR attachment.extension = 'gif' OR attachment.extension = 'png')) 
			WHERE thread.threadid IN
		(7936, 7916, 7935, 7934, 7933, 7932, 7931, 7930, 68, 5120, 7929, 7928, 7921, 7925, 7891, 7743, 7808, 7749, 7674, 6540, 7851, 7867, 7917);

MySQL Error  : Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
Error Number : 1140
Date         : Sunday, May 18th 2008 @ 01:53:07 PM
Script       : http://domain.com/forum/search.php?searchid=91
Referrer     : http://domain.com/forum/calendar.php
IP Address   : 79.131.140.29
Username     : username
Classname    : vb_database

can somebody tell me what that means and what can i correct? :erm:

--------------- Added [DATE]1211108653[/DATE] at [TIME]1211108653[/TIME] ---------------

Ok solution found here:
https://vborg.vbsupport.ru/showthread.php?p=1517207

thanks WEBclay