I don't know what changed as I have played from the library before. But Vista's defender is now blocking files when attempting to play music from my library. Typically Defender asks if I want to accept or reject incoming, but not this time. The following message is received:

Blocked events:
IPv4 UCP 192.16X.X.X Windows media player network sharing service TCP-In)? Incoming
IPv4 TCP 192.16X.X.X Network Discovery (NM Datagen-In) Prompt user for a decision corresponding this inbound traffic.

I checked my firewall entries and as you can see, tcp-out and tcp-in are enable.

VISTA firewall center:
Windows media player (TCP-out) Enabled
Windows media player Network Sharing Service (TCP-in) Enabled

Can anyone help me with this one?

The version of WMP that I consider a serious challenger for a media player is out. WMP 11 can be downloaded and is the best yet. I used the beta for several months and even if it is a bit of a memory hog, it does a good job of organizing,