htaccess anti leech help

Hello. I need some help with htaccess anti leech script

currently, this is what I'm using
RewriteEngine On
RewriteCond %{HTTP_REFERER} !^http://www.domain.com [NC]
RewriteCond %{HTTP_REFERER} !^http://domain.com [NC]
RewriteRule [^/]+.(zip|mpg|mpeg|jpg|jpeg|exe|avi|wmv|mp3)$ - [F]

I have also tried the following
RewriteEngine on
RewriteCond %{HTTP_REFERER}!^$
RewriteCond %{HTTP_REFERER}!^http://domain.com/.*$ [NC]
RewriteCond %{HTTP_REFERER}!^http://www.domain.com/.*$ [NC]
RewriteRule .*\.(zip|mpg|mpeg|jpg|jpeg|exe|avi|wmv|mp3)$ - [F]

and the simplified version of that
RewriteEngine on
RewriteCond %{HTTP_REFERER}!^$
RewriteCond %{HTTP_REFERER}!^http://(www\.)?mydomain\.com [NC]
RewriteRule .*\.(zip|mpg|mpeg|jpg|jpeg|exe|avi|wmv|mp3)$ - [F]

I am on a RaQ4 server which uses Apache and with both of those, I get an internal server error msg unless I put [NC] right after the first "$" but doing that makes the script useless

what I need the script to do is only allow access to the specified files by the listed domains and still allow the visitors from those domains to right click and use the save as option. Right now the scripts blocks access from non-authorized sites but does not allow right clicking. Any help on this will be appreciated.

no one huh?