The attached file was created by removing the video and subtitles from http://www.gnome.org/~hadess/mewmew-vorbis-ssa-cover.mkv.

0:00:01.173892830 28946      0x21c3660 ERROR                  totem bacon-video-widget-gst-0.10.c:354:bvw_error_msg: message = GStreamer encountered a general stream error.
0:00:01.174033830 28946      0x21c3660 ERROR                  totem bacon-video-widget-gst-0.10.c:356:bvw_error_msg: domain  = 3154 (gst-stream-error-quark)
0:00:01.174065601 28946      0x21c3660 ERROR                  totem bacon-video-widget-gst-0.10.c:357:bvw_error_msg: code    = 1
0:00:01.174094755 28946      0x21c3660 ERROR                  totem bacon-video-widget-gst-0.10.c:358:bvw_error_msg: debug   = matroska-demux.c(5059): gst_matroska_demux_loop (): /GstPlayBin2:play/GstURIDecodeBin:uridecodebin0/GstDecodeBin2:decodebin20/GstMatroskaDemux:matroskademux0:
stream stopped, reason not-linked
0:00:01.174126570 28946      0x21c3660 ERROR                  totem bacon-video-widget-gst-0.10.c:359:bvw_error_msg: source  = <matroskademux0>
0:00:01.174181870 28946      0x21c3660 ERROR                  totem bacon-video-widget-gst-0.10.c:360:bvw_error_msg: uri     = file:///home/philip/Desktop/temp.mkv
** Message: Error: GStreamer encountered a general stream error.
matroska-demux.c(5059): gst_matroska_demux_loop (): /GstPlayBin2:play/GstURIDecodeBin:uridecodebin0/GstDecodeBin2:decodebin20/GstMatroskaDemux:matroskademux0:
stream stopped, reason not-linked

From the attached error log:
0:00:00.963216314 29797      0x31a6780 INFO        GST_ERROR_SYSTEM gstelement.c:1762:gst_element_message_full:<uridecodebin0> posting message: No decoder available for type 'audio/x-vorbis, channels=(int)2, rate=(int)48000'.

I am missing a Vorbis decoder, but GStreamer is reporting the wrong error.