How protect user to post same (double) thread?

how to prevent same user to post same thread ?
Example:
SWF Decompile Expert 3.0.2.134

and this

SWF Decompile Expert 3.0.2.134

This is posted by same user today, same thread name and content...

Ok im try find any solution for this and im not find, because im download and edit code in one old mod... and i think that is works perfectly now...

What is this mod?
This is mod for vbulletin 3.8x and this modification will stoping stupid autoposter bots to post double thread...

Code: 
http://rapidshare.com/files/332456078/product-double_post_protection.zip.html

If you want you can test this mod, and write your opinion , or give me any other mod or solutions for stop posting doble thread?
AmN Reviewed by AmN on . Double Post/Thread Protection How protect user to post same (double) thread? how to prevent same user to post same thread ? Example: SWF Decompile Expert 3.0.2.134 and this SWF Decompile Expert 3.0.2.134 Rating: 5