ffmpeg error

ffmpeg version git-2014-11-26-5f30522 Copyright (c) 2000-2014 the FFmpeg developers
  built on Nov 26 2014 09:24:02 with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-11)
  configuration: --prefix=/root/ffmpeg_build --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --enable-gpl --enable-nonfree --enable-libfdk_aac --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-librtmp
  libavutil      54. 15.100 / 54. 15.100
  libavcodec     56. 13.100 / 56. 13.100
  libavformat    56. 15.100 / 56. 15.100
  libavdevice    56.  3.100 / 56.  3.100
  libavfilter     5.  2.103 /  5.  2.103
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
[matroska,webm @ 0x3566b40] Format matroska,webm detected only with low score of 1, misdetection possible!
[matroska,webm @ 0x3566b40] Read error at pos. 1 (0x1)
[matroska,webm @ 0x3566b40] EBML header using unsupported features
(EBML version 0, doctype (null), doc version 0)
file.mkv: Not yet implemented in FFmpeg, patches welcome