WampServer

This is a very strange problem I am having.

LAN setup:
Web Server (WAMP), plus some laptops and a NAS connected to a Netgear Router which shares my internet connection.

Netgear is configured to forward port 80 TCP/UDP to my Web Server internal IP address

Webserver Setup:
I installed WAMP, activated all the services (PHP, Apache2, Mysql)
- I can access the default WAMP homepage and all the administrative functions phpAdmin, etc.. from my localhost
- I can access the WAMP homepage from my laptop on the LAN and access phpinfo()
- I CANNOT access the WAMP homepage from the WAN (internet)
- I CAN, however create an html file (with no PHP) and SEE it from the WAN (internet)

What would cause PHP to work locally but not from remote machines? I havn't been able to find an answer to this. Permissions? http.conf?

I have not made any modifications to the default conf files so far. IT looks to be a PHP problem since regular HTML works fine accessed remotely. But if it is a PHP error why would it work from localhost AND from a laptop connected to the LAN? It isn't a router issue because the web server is responding to port 80 requests from the LAN and forwarding them correctly!