I would think that Firefox would show that but just to cover all bases, why don't you try using Internet Explorer 6 or 7?
Also, is this the only computer in the house? Can you attach a laptop or something else? All of this will verify where the problem is coming from.
Have you added the correct subnet to the firewall, to allow access?
What is the Ip address you are inserting into the browser? It should be either 192.168.0.1 or 192.168.1.1.