Different p2p apps use different ports. I've also heard several times of one person in a dorm being able to connect using LW but their roommate not. Sounds strange hey!!! I suspect it has something to do with allowances of the main router to allow a particular port to one particular comp. You could possible try another port, but then you'd need to change all your other settings within LW & your Firewall to the new port no. !!!