The NetGear MP101 can not be autodetected. You must specify the device type as MP101 in the server settings.
The MP101 will not function correctly under Vista. Short files will play okay, but playing a longer file will not continue on to the next song. The problem seems to be in the MP101, though how this can happen is unclear (it works fine with XP). The MP101 will not ask for the next song, it is not a firewall issue on Vista's side. This blog-post describes a third-party firmware for the MP101 that fixes the Vista bug: http://shazwanazizan.blogspot.com/2009/02/giving-back-to-society-netgear-mp101.html
The NetGear MP101 may not play back APE files compressed to insane level converted to MP3 format. The insane compression can take too long to decode with some computers so the MP101 will timeout. See this thread for more details.