I found how to get the movie playing actually : you simply click : play -> pause -> play :D if you do that before quickly enough you can watch you movie with subtitles ;) I hope this can help finding the source of the bug
-- Internal data flow error. https://launchpad.net/bugs/70223 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs