Added error log message when video can't be demuxed (#435).
Added error log message when video can't be demuxed (#435).

svn path=/trunk/libavg/; revision=9250

yyd01245/libavg,libavg/libavg,yyd01245/libavg,hoodie/libavg,hoodie/libavg,scotty007/libavg,scotty007/libavg,yyd01245/libavg,scotty007/libavg,libavg/libavg,scotty007/libavg,th3infinity/libavg,hoodie/libavg,libavg/libavg,hoodie/libavg,th3infinity/libavg,yyd01245/libavg,libavg/libavg,th3infinity/libavg,th3infinity/libavg