Help | Error Number : 1064

[mtirca]

Hello,
Today I deleted a number of topics from the database through the forum of course and I suddenly felt Error
http://puu.sh/4jQr9.png

Database Error Database error
The Onone.co.il database has encountered a problem.
Please try the following:
Load the page again by clicking the Refresh button in your web browser.
Open the www.xdx.co.il home page, then try to open another page.
Click the Back button to try another link.
The www.onone.co.il forum technical staff have been notified of the error, though you may contact them if the problem persists.

We apologise for any inconvenience.

Database error in vBulletin 4.2.1:

Invalid SQL:
SELECT COUNT(DISTINCT post.userid) as count FROM post AS post WHERE post.threadid = AND post.visible = 1 AND post.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 'AND post.visible = 1 AND post.userid !=' at line 1
Error Number : 1064
Request Date : Thursday, September 5th 2013 @ 07:05:25 PM
Error Date : Thursday, September 5th 2013 @ 07:05:25 PM
Script : http://www.xdx.co.il/
Referrer :
IP Address : XXXX
Username : XDX
Classname : vB_Database
MySQL Version : 5.5.31

What do you do in this situation? How to fix it is very urgent for me Member No. 1 and is my user
Quick reply'd love huge thank helpers

Upgrade and it still did not help, what to do?!
Version is: 4.2.1