Database error on merging users

[Bizzy]

I read a few other similar topics to this one but nothing quite the same.

A little background. This user prior to upgrading to 3.6.8, had something funky happen to is account. His user name is unclickable even by me and his post count shows n/a. I don't know exactly when it happened or what caused this to happen. Here's a link to a post he has made.
http://www.shoforum.com/showpost.php...78&postcount=2

He has no problems posting and as far as I know he is able to send PMs but I don't know if he is able to receive any back or not.

I tried to create a new user name for him, then merge the two together so he wouldn't lose his posts or reputation. When trying to merge the old user account into the new one I get the following error:

Database error in vBulletin 3.6.8:

Invalid SQL:

SELECT forumid, emailupdate
FROM subscribeforum
WHERE userid =;

MySQL Error : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 3
Error Number : 1064
Date : Friday, October 5th 2007 @ 10:37:10 PM
Script : http://www.shoforum.com/admincp/user...=reallydomerge
Referrer : http://www.shoforum.com/admincp/user...php?do=domerge
IP Address : **removed**
Username : **My user name**
Classname : vb_database

I've tried Admin CP -> Maintenance -> Repair/Optimize Tables -> Check All -> Continue, but it doesn't change anything and I still get the database error.

Help?

Edit: I'm not able to send him a PM. I get another database error when I try to do that via the admincp.

Database error in vBulletin 3.6.8:

Invalid SQL:
INSERT INTO pm (pmtextid, userid) VALUES (165669, );

MySQL Error : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1
Error Number : 1064
Date : Friday, October 5th 2007 @ 11:12:28 PM
Script : http://www.shoforum.com/private.php?do=insertpm&pmid=
Referrer : http://www.shoforum.com/private.php?do=newpm&u=12899
IP Address : **removed**
Username : **my user name**
Classname : vb_database

[Steve Machol]

SQL Syntax errors are almost always related to modified code. To troubleshoot this, the first thing you need to do is remove any hacks or plugins, then see if you still have this problem.

If so, reupload all the original vB non-image files (except install.php). Make sure you upload these in ASCII format and overwrite the ones on the server.

Next, create a new style and choose no parent style. This will force it to use the default templates. Finally empty your browser cache, close all browser windows then try again. Make sure you change to the new style and view your forums with it. Do you have the same problem?