Hello,
yup, I'm a game creator, not a network engineer, so I don't know all routers available on the market. Actually, I never have any router, so I don't have any practical knowledge of them, only a bit of theory.
But I know the site which gives you a step by step configuration (
www.portforward.com ), and it seems easy enough to follow the instructions. If something goes wrong, I can't help you further. If I had your computer under my eyes, I could probably figure out what's going wrong, but unfortunately, it's not possible.
But Internet is full of forum with people willing to help you (when you ask nicely), and you may find someone to help you to configure your router, for example, here :
http://forum.portforward.com/YaBB.cgi
or here :
http://forums.speedguide.net/forumdisplay.php?f=38
etc, etc...