VPN through Netopia 3387WG-ENT router

I have a Netopia 3387WG-ENT router on my SBS2003 server network, I setup VPN service on teh server, and installed the VPN connection on my WinXp laptop.

I am able to connect through the VPN, but can not connect to resources on teh server (shared drives etc.) when I look at the server it shows errors saying the VPN connected, but GRE Protocal is being blocked.

How do I setup GRE protocol through the 3387WG-ENT? I’ve looked through Netopia/mororola’s website but nothing.

Thanks for your help in advance.