Firstly read your router manual in its entirety. I'll need the full model number (including the letters) to link the manual for you. Then research lan configurations if you are not familiar with them.
Ah, it is a wireless router? These are notoriously bad for stable multuiplayer gaming. CAT-5E works just great up to 100 meters. (and is 1000x more secure, since that seems to be an issue for you)
The only ports required for the D2 are 2300-2400 and 47624, thats it. (directplay ports only - Blame MS for the range)
Configure your lan statically, DO NOT use DHCP and the DMZ. Forward the mentioned port ranges to the client PC with SFC installed. Your router must support port range forwarding. Ensure your router has the latest firmware.
Do not run software firewalls period. (They can only add lag and a false sense of security).
Works every time.
OOPS, just noticed this post:
Thanks for the help, and your right...I finally just checked a reference on dlinks site, and put in all of the ports, and it connected just fine, but I couldn't find GW5...but at least I know it works...
Kana
What I suggest still goes however. There is a tech support acronym: "RTFMS"...