You should turn off the xp firewall and allow limewire access through the norton firewall. This thread should help
Finally solved my connection problem: Configuring Norton Internet Security.
To turn off the windows firewall, from you desktop go to Start>Control Panel>Security Center>Windows firewall> tick the off button then click ok. It will warn you not to turn it off but if you have norton running then it's ok.
Hope this helps
. Post back if it doesn't.