Dsl and router being stupid.

I am trying to get a internet connection to a pc on our Zoom DSL modem and Linksys wrt54g routered network. I have tried port forwarding on both the modem and router to the 4899 port RAdmin is desiring. I have also tried using tightvnc with ports 5900 and 5800 open on both. I have all ports required allowed in the firewall on both my Windows XP pro machines. With no luck connecting. Any help would be greatly appreciated.