Just make sure that the XP firewall is off, it'll conflict with Norton & cause trouble.
You might want to make sure of your Norton configuration (sorry, I can't help you there - I don't use it), or even try reconfiguring it since you're having trouble with it in another area too. Check out the links below for some more info about this
http://www.limewire.com/english/content/firewalls.shtml
http://service1.symantec.com/SUPPORT...rc=bar_sch_nam


You could always try port forwarding, rather than enabling UPnP...see if that makes any difference. Follow the instructions at the site below. Just remember to set up a static IP address first (you'll find instructions for that within the same link) or it won't work.
http://www.portforward.com/english/r...G/Limewire.htm

See how that goes & post back if you've still got problems