the firewall configuration could well be the problem.
Fibs uses port 4321 for connection.
Could you give som more information about your situation (os, network configuration, firewall, etc.?)
you can try to use telnet from windows to connect to fibs.com port 4321.
If you get a login you should be able to use 3dfibs or javafibs.
Whetr you use parlorplay you are useing port 80 (webpage).. so that could explain why that is working and the software isn't.