Hi there

Sounds like it could be a Gateway or DNS issue, is there anywhere you can enter the gateway and DNS addresses in the Belkin?
Other thing to check is the ADSL modem and the Belkin are not on the same subnet ie. the ADSL modem should not be 192.168.2.X. This is because the Belkin is a router and won't route to addresses in the same subnet.

Good luck
Dale