Freeze mkv file and status 11

I just copied Milk and Ironman to my atv and tried to open them via Boxee (which I find amazing!!). They start off fine but freezes soon after. Before the full freeze the audio goes unsync of video and it is impossible to watch. After a while i get the status 11 message. What can I do to avoid this.

I tried with another mkv file and to play this wirelessly from my Home server. That worked just fine. How come???

The bitrate on Milk is 7290 (located on the atv)
The overall bitrate on Kung Fu Panda is 1651 (located on HomeServer)