Waldo, here's what I did to finally get WMP to stream a song:
In WMP 'preferences', under 'options', then under 'Network' tab, I checked the boxes next to 'Multicast', 'UDP', 'TCP', and 'HTTP', then I set it to 'Autodetect' protocol, and it worked.
Aw shoot, I shoulda known... The new version defaults to HTTP streaming...
I was almost getting to that with the firewall/port blocker question!
I'll add that to the FAQ for the future.
Thanks bud.
W.