Blocking Bandwidth Thieves Options

[MR. T]

Hi,

I am trying to block hotlinking of my images and files so it only allows me to hotlink on my main side and 2 subdomains. For example these are my 3 domains.

1. http://maindomain.com
2. http://forum.maindomain.com
3. http://media.maindomain.com

All my images and files are stored on my media subdomain and my other 2 sites 1. and 2. ask for the files. I have tried this script in a .htaccess file but it wont work.

CODE

  RewriteEngine On

  RewriteCond %{HTTP_REFERER} !^$
  RewriteCond %{HTTP_REFERER} !^http://(www\.|forum\.|media\.)?maindomain\.com [NC]

  RewriteRule \.(bmp|gif|jpe?g|png)$ /images/linking.jpg [R=302,L]
  RewriteRule \.(swf|mp3|wmv|zip)$ - [NC,L,F]

Any ideas why it wont work, Please?