I did some research & it appears your surfboard does not support UPnP. The article I saw is only 2 weeks old. The answer is to forward a port within the Motorola.

Steps must be in this order & a static ip is the very first & most important step to do:

1. Setting up a Static ip for Windows XP

2. Find your Motorolla model here, click on link, then find LimeWire on the following page & click that link & follow directions: PortForward.com - Free Help Setting up Your Router or Firewall

3. I think you need to reboot your Motorolla after doing this process to both save & get the new firewall rules into action.