I'm currently using the latest versions of SlimRoku and MPlay. Quite often I run into a situation where my network connections are fine, ie photos display, SlimRoku loads and I can access my music library, but when I try to play a track I get "Music playback unavailable". If I try to use MPlay, the video plays correctly, but there is no sound. I can get back to normal by re-booting.
Anyone know what causes this?