Problem with referrer and search strings

[sevenmix]

Hi

Somebody is attacking my website referring an swf to inexistent urls, this is an example:

My site: http://forobeta.com/blogger/?el-chofer/608/

When the problem is that this url doesnt existe: "?el-chofer/608/"

02/01/12 20:42

380

http://img69.xooimage.com/files/7/2/a/foroe-303aab7.swf (this archive is the referrer, checked in cpanel)

I tried to block this in htaccess with any luck:

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_REFERER} xooimage\.com [NC]
RewriteRule .* - [F]
</ifModule>

If you see the problem is that the search strings are making my server really slow and some times inaccesible because php try to process it.

Do you have any idea how to solve this?