Hi Geordief
Ok, let me think. I have seen this a few times now. Ok, you can find out what a machines internal IP is by doing the following:
1.Go to Start
2.Programs
3. Accessories
4.Command/MSDos prompt.
5. In the black DOS box type in ipconfig for getting the ip of one machine.
Type ipconfig /all to get the Gateway and Internal IP of the machine.
Put this into your browser.... http://(number)
It will come up with username and password.
Username is = username or password
password is = password or (blank)
Ok once you are in you will need to go to al of the tabs until you find the section on port farwarding. This looks something like this computer addy, tcp/udp, port number.
Once you have done that and they are forwarded correctly it will work.
Oh and by the way the computer addy is different from the gateway addy so please make sure you write both of them down.
Good luck and please let me know how you go.