Update 28 Sep 2013: This issue has now been resolved with the latest PandoraJam 2.1 beta (build 650), so this note is only for historical reference. Hat tip to Joseph in the comments and thanks to Quentin over at RogueAmoeba and Jason at Industrious One for the workaround.
If you stream audio to your Apple TV from PandoraJam or other non-Apple software applications, we recommend that you do not update to Apple TV version 6.0.
Apple’s latest update appears to stop third party applications from streaming audio. Further investigation is required to determine the exact cause and potential solutions. Thank you.