Forum 3.8.6 to 4.0.6 db error on forumhome help!!

[محروم.كوم]

I just upgraded my site and I cannot get to the forums. I can get into the admincp fine but the forums don't work. This is the error I get.

Database error in vBulletin 4.0.6:

Invalid SQL:
SELECT COUNT(*) AS count FROM attachment WHERE visible = 0;

MySQL Error : Unknown column 'visible' in 'where clause'

Error Number : 1054
Request Date : Thursday, August 19th 2010 @ 04:46:49 PM
Error Date : Thursday, August 19th 2010 @ 04:46:49 PM
Script : http://www.redliners.ca/vb4/forum.php
Referrer :
IP Address : 74.59.122.44
Username : DannyITR
Classname : vB_Database
MySQL Version : 5.0.86


Furthermore I ran into some trouble while upgrading.

1) it told me the blog was already installed (it was). I deleted the blog tables and it let me continue. Had I actually been using the blog I'm concerned I would have lost all my data.
2) it told me that the CMS was already installed (how is this possible, there is no CMS on vb 3.8.x). I deleted the CMS tables and it let me continue. I'd just like to know what caused these problems. __DEFINE_LIKE_SHARE__