After I sent in my last reply, I tried it with the XP firewall off and got the same result.

The more I work on this, the more it seems to be something going on in the router. How else would the receiver and server be getting the correct IP addresses but still not be able to see each other? Maybe the problem is that I need to open up some ports in my router, but which ones?

I'll try opening up the NFS port in my router and see what happens.