The brick wall means that LW's detecting a firewall. It could be a software firewall not configured properly or it could be an internal firewall within a modem/router. This can effect your searches & downloads & it will definitely effect other people downloading from you.

Double check that the XP firewall's configured properly
Firewall setup

You could port forward through your modem, chances are that this would get rid of the firewall problem. Once you've followed the instructions for port forwarding
http://www.portforward.com/english/r...0/Limewire.htm
you'll have to choose the 'manual port forward' option in LW's tools > options > advanced > firewall config. Make sure that you enter the same port number as LW's listening port & apply to save the change.

There's a lot of good info here about setting up LW for best performance
Configuring LW for best performance