Playback works in PlaceShifter, not in Server or Extender

[VCRUser]

I have various videos (downloaded from YouTube and copied to my server) that playback just fine via Placeshifter, but show various problems when trying to play them on the HD200 or on the server. In some cases, they actually crash the extender; on the server they might either throw an error message (playback exception) or play but without sound.

In looking over the formats reported by Sage, I'm not seeing any consistent differences between those that play and those don't:

The Youtube videos tend to show as Quicktime h.264 - some play and some don't. Sometimes I run them through Handbrake, which sometimes helps and sometimes doesn't. At least one that works fine wherever I play it, it is shown as matroska h.264. Audio reported as aac 44.1, various bit-rates plays sometimes, not others. Video bitrates and resolutions likewise show no pattern of playing/not playing.

Thoughts on how to trouble-shoot this would be appreciated, along with any experiences with similar problems.

Some log entries that look to be about the right time I last generated the error. I'm not sure what they mean or even if they're related to the problem:

Mon 3/28 0:03:47.702 [MediaServerConnection@15c8c9ca] Error in MediaServerConnection of :java.io.IOException: An existing connection was forcibly closed by the remote host
Mon 3/28 0:03:47.702 [MediaServerConnection@3e48c974] Error in MediaServerConnection of :java.io.IOException: An existing connection was forcibly closed by the remote host
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] java.io.IOException: An existing connection was forcibly closed by the remote host
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sun.nio.ch.SocketDispatcher.read0(Native Method)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sun.nio.ch.SocketDispatcher.read(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sun.nio.ch.IOUtil.read(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sage.MediaServer$Connection.readLineBytes(MediaServer.java:241)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sage.MediaServer$Connection.run(MediaServer.java:1410)
Mon 3/28 0:03:47.703 [MediaServerConnection@15c8c9ca] at sage.Pooler$PooledThread.run(Pooler.java:254)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] java.io.IOException: An existing connection was forcibly closed by the remote host
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sun.nio.ch.SocketDispatcher.read0(Native Method)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sun.nio.ch.SocketDispatcher.read(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sun.nio.ch.IOUtil.read(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sage.MediaServer$Connection.readLineBytes(MediaServer.java:241)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sage.MediaServer$Connection.run(MediaServer.java:1410)
Mon 3/28 0:03:47.703 [MediaServerConnection@3e48c974] at sage.Pooler$PooledThread.run(Pooler.java:254)