My guess is your Westell router is the unknown firewall. In my experience on these forums, Westell routers (whether they support UPnP or not) are best port forwarded. (1) Very first and most important step in port forwarding is setting up a static ip; see Setting up a Static ip for Windows XP (click on link). 2. Next step is to find your model of Westell, then find it listed at far right column near bottom of this page: PortForward.com - Free Help Setting up Your Router or Firewall then find LimeWire listed on the following page after you click that model's link. The LW link will lead you to the next set of instructions for setting up a firewall rule for LW's needed ports. (3) is at start of previous step which is settings for LW. (4) Last step is saving settings for your router, you may need to reboot your router ... not sure about Westell.

The model of Westell will most likely be shown on the actual router/modem. Look at the top or sides. You probably also received a manual with it too.