The AVI file is a PHP script which validates the refferer. If there is no refferer, it sends a redirect instead. Look:
vhosts]# telnet
www.pornvideoworld.com 80
Trying 216.131.82.98...
Connected to pornvideoworld.com.
Escape character is '^]'.
GET /avi/xxx.avi HTTP/1.1
host:
www.pornvideoworld.com
HTTP/1.1 302 Found
Date: Wed, 13 Feb 2002 04:02:44 GMT
Server: Apache/1.3.19 (Unix) (Red-Hat/Linux) mod_ssl/2.8.1 OpenSSL/0.9.6 FrontPage/4.0.4.3 PHP/4.0.4pl1
X-Powered-By: PHP/4.0.4pl1
Location: fuck.html
Transfer-Encoding: chunked
Content-Type: text/html
0
Connection closed by foreign host.