Background Audio refuses to play stream on WP8

I have a Windows Phone 7 app that plays an internet radio stream just fine on a WP7 device. If you run that app on WP8, it simply refuses to play. I've tried upgrading the app to be an actual WP8 app just to see if this makes a difference, but it doesn't seem to.

The exception I'm getting is a COMException with a Message of Exception from HRESULT: 0xC00D2EE0

The stacktrace is:

   at Microsoft.Phone.BackgroundAudio.BackgroundAudioPlayer.Play()
   at HotRadioAgent.AudioPlayer.OnUserAction(BackgroundAudioPlayer player, AudioTrack track, UserAction action, Object param)
   at Microsoft.Phone.BackgroundAudio.AudioPlayerAgent.CallOnUserAction(ParameterPropertyBag parameters)
   at Microsoft.Phone.BackgroundAudio.AudioPlayerAgent.Invoke(Uri uri, ParameterPropertyBag parameters)
   at Microsoft.Phone.BackgroundAgentDispatcher.AgentRequest.Invoke()
   at Microsoft.Phone.BackgroundAgentDispatcher.InvocationThread()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

The stream itself is being played through an Audio Playback Agent (not an Audio Streaming Agent), which as mentioned, works fine on a WP7 device.

The stream in question is http://stream1.tune-in.co.uk:7002/;stream.mp3

If any audio gurus could help me out on this one it would be greatly appreciated.