Help pls...BMax and BNet Module

Any ideas why this doesnt work?
Wrote a simple TCP client/server programm which works fine on same PC (enter IP and then send a string to server programm).

Then i gave it a try on two PCs, where the client failed to connect to server.
Both PCs are using same account to get into the net via a DSL Router (no Firewall etc. installed on both PCs).

I am quiet new to network programming. Maybe its because both PCs are using same provider account and a router?
Theres no problem to play World of Warcraft etc.
simulatenous. I realy have no clue why i cant get a simple connection to work here:-/

You may ensure there's no NAD security system installed. Windows XP SP2 can disable some ports (personal firewall), you may try using some standar port as 80.

Thank you, you are right.
Opening a Port at Server side did it.