PopMal, have you tried port forwarding?
http://www.portforward.com/english/r...G/Limewire.htm
Don't forget to set up a static IP address. There are instructions within the link

Make sure that your XP firewall is configured. As stief said, you shouldn't run without a firewall!
Firewall setup

Configure your firewall & then have a try with port forwarding. Let us know how it goes!