Just download any Magnetmix file...it's just a test to see how fast your download is (things should download quickly).

XP has it's own firewall, make sure it's configured to allow LW
User Cant Connect - LimeWire

HughesNet have a FAP, maybe you've been hit by that?
The Fair Access Policy (FAP)

Try changing ports. In LW tools > options > advanced > firewall config. Change LW's listening port to 64049 (or something in the range of 49152 - 65535) > Apply > ok.

You could try port forwarding for your router. The instructions are here.
Port Forwarding for the Dlink DI-524
Don't forget the step of setting up a static IP address. LW's listening port, port in the 'manual port forward' box & port forwarded within the router all have to be the same number