Hello,
Thanks for the suggestions. The combination of checking /etc/network/interfaces and verifying that rpcbind was listening on 127.0.0.1 led me in the right direction, and boy do I feel silly...
Somehow, my interfaces file was missing the loopback entry, so the loopback interface showed in the "ifconfig" output but it wasn't actually up. I added these lines:
auto lo
iface lo inet loopback
Then, after "ifup lo", everything just worked.
I think I wrote the interfaces file from scratch and copied it over the original, and of course, I didn't include the loopback interface. *Sigh*.
Thanks again!
- Dave