Forum database errors after upgrading
 

I tried upgrading to 4.0.5 from 3.8.6 a couple days ago, the installation completed but then I noticed the following error in my admincp:

Code:
Database error in vBulletin 4.0.5:

Invalid SQL:

SELECT COUNT(*) AS count
FROM attachment AS attachment
INNER JOIN post AS post USING (postid)
WHERE attachment.visible = 0;

MySQL Error : Unknown column 'postid' in 'from clause'
Error Number : 1054
Request Date : Sunday, July 18th 2010 @ 08:14:56 PM
Error Date : Sunday, July 18th 2010 @ 08:14:56 PM
Script : http://www.bantcess.com/admincp/index.php?do=home
Referrer : http://www.bantcess.com/admincp/
IP Address : 76.168.249.69
Username : Tgone
Classname : vB_Database
MySQL Version : 5.0.91-community
After seeing this, I removed the 4.0.5 files and uploaded the old 3.8.6 files. However, it appears that my database was changed by the original upgrade attempt, and now the system thinks I'm running 4.0.5, as seen below when I try to make a new thread:

Code:
Database error in vBulletin 4.0.5:

Invalid SQL:
SELECT wordid, title FROM word WHERE title IN ('test','test','test');

MySQL Error : Table 'bantscom_vbulletin.word' doesn't exist
Error Number : 1146
Request Date : Sunday, July 18th 2010 @ 08:15:35 PM
Error Date : Sunday, July 18th 2010 @ 08:15:35 PM
Script : http://www.bantcess.com/newthread.php?do=postthread&f=4
Referrer : http://www.bantcess.com/newthread.php?do=newthread&f=4
IP Address : 76.168.249.69
Username : Tgone
Classname : vB_Database
MySQL Version : 5.0.91-community
I've searched around the forums and found people with similar problems, but I can't find a fix. At this point, all I went to do is go back to my original 3.8.6 forum, but my database isn't working with either the 3.8.6 and 4.0.6 software! Unfortunately, I made a backup before I attempted the 4.0.6 upgrade but it's corrupt. Doe anyone have any ideas on how I can repair my database so it works with 3.8.6 again?