I have unlocked S2 on both PC.
My IP in my Local Network is automatic (169.254.234.86), but it works if I start on any PC a demo server.
I can also create a S1 or S2 server, but when I try to connect from the other PC it says that it is a not valid IP (But this IP is valid on a demo server).
I have XP home o both PC and I have made a local network with my two PC connecting them directly.
I think it is not a problem with my network, because it works great if I create a demo server.
I´m going to try to change my IP to put it in range...