If you go to the Connection Troubleshooter in WLM (Tools > Options > Connection > Start), is it successful? I'm guessing there may be problems with the key ports.
Also, what firewall are you using?
Oh and make sure the firmware for your router is up to date. May be
here, but you'll need the specific name of the router in order to get the correct firmware.
You could always try on a Belkin support forum.