If your are sharing your internet connection and your router is doing NAT, then you are sharing the same IP address, and since I have not seen anything that allows for the port numbers to be changed in PTW, then you are probably stuck. In order for me to be able to play over the net, behind a router performing nat I had to statically map all the ports used by PTW to my specific machine.
Check out
http://apolyton.net/forums/showthrea...threadid=66350
for nat issues and how to resolve them..
Good luck, if you find a way to change the used port numbers let me know
BlackOut