Quick update of progress. The http urls now works (don't ask what I had missed) but file urls are still not working.

My interpretation of the debug log is that the file url is appended to the current directory.

[669 9 4 remoted_parse: sock:-77 r_sock0:5 r_sock:-1 br:70 br0:71 bl0:5 b:LOAD2 file:///home/user/MyDocs/Podcasts/Brainy%20Gamer/bgpodcast38.mp3 bp:file:///home/user/MyDocs/Podcasts/Brainy%20Gamer/bgpodcast38.mp3]
[669 9 4 /home/user/MyDocs/.sounds/Christian Gabel/1900/file:///home/user/MyDocs/Podcasts/Brainy%20Gamer/bgpodcast38.mp3]

With local files the log looks like this and the music starts:

[1230 9 4 remoted_parse: sock:-77 r_sock0:5 r_sock:-1 br:61 br0:62 bl0:5 b:LOAD2 /home/user/MyDocs/Podcasts/Brainy Gamer/bgpodcast38.mp3 bp:/home/user/MyDocs/Podcasts/Brainy Gamer/bgpodcast38.mp3]
[1230 9 4 /home/user/MyDocs/Podcasts/Brainy Gamer/bgpodcast38.mp3]

As http now works the service is quite functional for my use cases and I will upload it after some cleanup.