I have no idea whether the SMC has UPnP abilities. But it's always safest to manually port forward. Follow the directions here carefully http://www.portforward.com/english/r...R/Limewire.htm

Also, if you're using Windows XP then you should configure it to allow LW full access; Firewall configuration instructions (click on link) (Oh & if you have another firewall then decide between XP firewall & the other. Running 2 firewalls is not recommended. All firewall companies give that advice as it can result in less security as they clash.)

After these things, the brick wall should disappear.