I am having the same problem the movie server needs to support mk3d playback, as I have tried to play a file with the file extension changed to mkv, it detects it is a 3D movie, but when ever I try to play it in 2D or 3D as it asks me how I want to watch, it refuses to play and just stops and reverts back to the movie selection screen.
Changing the file extension to mkv isn't a good option anyhow as players on a PC need it to be mk3d to play in 3D as they do not detect it as 3D and only play it as 2D.
How you have not given support for this format from the start is beyond me.