[htscpl]

Can anyone tell me where to look for the source of this error. I get about 10-15 noticies a day with the same error message

Database error in vBulletin 3.8.6:

Invalid SQL:

SELECT
IF(votenum >= 1, votenum, 0) AS votenum,
IF(votenum >= 1 AND votenum > 0, votetotal / votenum, 0) AS voteavg,

thread.threadid, thread.title AS threadtitle, thread.forumid, pollid, open, postusername, postuserid, thread.iconid AS threadiconid,
thread.dateline, notes, thread.visible, sticky, votetotal, thread.attach, thread.lastpost, thread.lastposter, thread.lastpostid, thread.replycount, IF(thread.views<=thread.replycount, thread.replycount+1, thread.views) AS views,
thread.prefixid, thread.taglist, hiddencount, deletedcount
,
event.eventid, event.recurring, event.recuroption, event.customfields, event.utc, event.dateline_from, event.dateline_to,
subevent.subscribeeventid, calcustom.title AS cctitle, calcustom.calendarcustomfieldid AS ccccf
FROM thread AS thread

LEFT JOIN event AS event ON (thread.lv_vb_eventforums_eventid = event.eventid AND post.postid = thread.firstpostid)
LEFT JOIN subscribeevent AS subevent ON (subevent.eventid = event.eventid AND subevent.userid = 0)
LEFT JOIN calendarcustomfield AS calcustom ON (calcustom.calendarid = event.calendarid)
WHERE thread.threadid IN (0)
ORDER BY sticky DESC, lastpost DESC;

MySQL Error : Unknown column 'post.postid' in 'on clause'
Error Number : 1054
Request Date : Sunday, November 20th 2011 @ 01:48:00 PM
Error Date : Sunday, November 20th 2011 @ 01:48:00 PM
Script : http://xxx/vbulletin/forumdisplay.php?f=46
Referrer :
IP Address : xxx.xx.xx.xxx
Username : Unregistered
Classname : vB_Database
MySQL Version :

Thanks in advance for any help.