Changing read marking type breaks site

[محروم.كوم]

I am attempting to convert from inactivity/cookie based thread read marking to database thread read marking (automatic). When I attempt the change, all forums start failing with the following error:

Database error in vBulletin 3.8.4:
Invalid SQL:
SELECT thread.threadid, thread.forumid,
IF(threadread.readtime IS NULL, 1263537825, IF(threadread.readtime < 1263537825, 1263537825, threadread.readtime)) AS threadread,
IF(forumread.readtime IS NULL, 1263537825, IF(forumread.readtime < 1263537825, 1263537825, forumread.readtime)) AS forumread,
thread.lastpost, subscribethread.subscribethreadid
FROM vb35_thread AS thread,
vb35_subscribethread AS subscribethread
LEFT JOIN vb35_threadread AS threadread ON (threadread.threadid = thread.threadid AND threadread.userid = 1)
LEFT JOIN vb35_forumread AS forumread ON (forumread.forumid = thread.forumid AND forumread.userid = 1)
WHERE subscribethread.threadid = thread.threadid
AND subscribethread.userid = 1
AND thread.visible = 1
HAVING thread.lastpost > IF(threadread > forumread, threadread, forumread);

MySQL Error : Unknown column 'thread.threadid' in 'on clause'
Error Number : 1054
Request Date : Sunday, January 17th 2010 @ 10:43:45 PM
Error Date : Sunday, January 17th 2010 @ 10:43:45 PM
Script : edit
Referrer : edit
IP Address : 212.143.139.191
Username : admin
Classname : vB_Database
MySQL Version : 5.0.22-log

When I switch it back to cookie based, all's fine. Ideas? __DEFINE_LIKE_SHARE__