Strange htaccess Problem

I have a directory with movies protected by the following htaccess file

---
RewriteEngine On
RewriteCond %{HTTP_REFERER} !^http://([a-z0-9-]+\.)*mydomain.com/ [NC]
RewriteRule /* http://%{HTTP_HOST}/ [R,L]
---

The idea is that you can't directly access the dir with the movies, you have to come from mydomain.com.

The protection works fine, no problem there.

However, if I try to download a movie using 'save target as', I can't. I get a html file in stead of the avi or mpg.

I have no idea how to fix this. Any ideas? Thanks in advance.