For some reason when I try to watch a file with the following FFmpeg data I get a "Unsupported Data" error message.

FFmpeg version git-N-28463-gc5dcb3d, Copyright (c) 2000-2011 the FFmpeg developers
built on Apr 20 2011 10:16:52 with gcc 4.4.2
configuration: --enable-memalign-hack --arch=x86 --target-os=mingw32 --cross-prefix=i686-mingw32- --enable-static --disable-shared --enable-zlib --disable-ffprobe --disable-ffplay --prefix=/media/windows/ffmpeg --enable-libmp3lame --enable-libx264 --enable-gpl --extra-libs='-lx264 -lpthread' --enable-runtime-cpudetect --pkg-config=pkg-config
libavutil 50. 40. 1 / 50. 40. 1
libavcodec 52.120. 0 / 52.120. 0
libavformat 52.108. 0 / 52.108. 0
libavdevice 52. 4. 0 / 52. 4. 0
libavfilter 1. 79. 1 / 1. 79. 1
libswscale 0. 13. 0 / 0. 13. 0
[matroska,webm @ 01824fe0] Unknown entry 0x63C9
Last message repeated 1 times
[matroska,webm @ 01824fe0] Estimating duration from bitrate, this may be inaccurate
Input #0, matroska,webm, from 'G:\Videos\TV Series\Smallville\Season 10\18 Booster.mkv':
Duration: 00:41:33.00, start: 0.000000, bitrate: 384 kb/s
Stream #0.0(eng): Video: h264 (High), yuv420p, 1280x720, PAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
Stream #0.1(eng): Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s (default)
Metadata:
title : English
Stream #0.2(eng): Subtitle: [0][0][0][0] / 0x0000
Metadata:
title : English
At least one output file must be specified


---> DB Level Info: 31
But this file with what looks to me to be the same settings plays just fine.
FFmpeg version git-N-28463-gc5dcb3d, Copyright (c) 2000-2011 the FFmpeg developers
built on Apr 20 2011 10:16:52 with gcc 4.4.2
configuration: --enable-memalign-hack --arch=x86 --target-os=mingw32 --cross-prefix=i686-mingw32- --enable-static --disable-shared --enable-zlib --disable-ffprobe --disable-ffplay --prefix=/media/windows/ffmpeg --enable-libmp3lame --enable-libx264 --enable-gpl --extra-libs='-lx264 -lpthread' --enable-runtime-cpudetect --pkg-config=pkg-config
libavutil 50. 40. 1 / 50. 40. 1
libavcodec 52.120. 0 / 52.120. 0
libavformat 52.108. 0 / 52.108. 0
libavdevice 52. 4. 0 / 52. 4. 0
libavfilter 1. 79. 1 / 1. 79. 1
libswscale 0. 13. 0 / 0. 13. 0
[matroska,webm @ 00354fe0] Unknown entry 0x63C9
Last message repeated 1 times
[matroska,webm @ 00354fe0] Estimating duration from bitrate, this may be inaccurate
Input #0, matroska,webm, from 'G:\Videos\TV Series\Smallville\Season 10\17 Kent.mkv':
Duration: 00:41:47.00, start: 0.000000, bitrate: 384 kb/s
Stream #0.0(eng): Video: h264 (High), yuv420p, 1280x720, PAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
Stream #0.1(eng): Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s (default)
Metadata:
title : English
Stream #0.2(eng): Subtitle: [0][0][0][0] / 0x0000
Metadata:
title : English
At least one output file must be specified


---> DB Level Info: 31
I'd really love some help figuring this out.