Found out some more info about this problem.

The Master Playlist File will cause an error when accessed after a cold boot and it is 18873 bytes or larger. Once it has been truncated (even one byte will suffice) it will then work perfectly until the next re-boot, even if it is subsequently made larger again.

The MPF works perfectly every time if its size is 18872 bytes or less.

I cannot see that the server has anything to do with this.

Also, if I try to access Select Music/Title (over 10,000 songs) the player application crashes and re-starts.

Are these some fundamental limits to the Receiver's player application? I know there are some limitations and I can accept or work around them, but I just don't understand why the playlist limit exists only until it accesses a smaller (below the limit) file then runs perfectly on much larger files until a cold re-boot.

Anyone any clues?