vbulletin database error

Since the last update (2.6.5+) I have this error reported by email 4-5 times a day.
Its not always the same game or same user.

Database error in vBulletin 3.6.8:

Invalid SQL:
SELECT * FROM tournament WHERE tid =;

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 19th 2007 @ 09:13:28 AM
Script : http://www.lelounge.ca/index.php?act=Arcade&do=newscore
Referrer : http://www.lelounge.ca/arcade/targetbowlingTh.swf
IP Address : 207.134.102.142
Username : caro1919
Classname : vB_Database

[tarball]

i'm getting this kind of message 10 times a day!

[C.ooder]

ware show thees message

[tarball]

An other exemple:

Database error in vBulletin 3.6.8:

Invalid SQL:
SELECT * FROM tournament WHERE tid =;

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 : Tuesday, December 18th 2007 @ 03:59:49 PM
Script : http://www.lelounge.ca/index.php?aut...e&do=savescore
Referrer : http://www.lelounge.ca/arcade/pyrami...-ancientJS.swf
IP Address : 64.18.166.202
Username : yechane
Classname : vB_Database