ffmpeg -i 21.DEA GIGA SHOW 2008.avi  hasani.mpg
FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --enable-gpl --enable-pp --enable-pthreads --enable-vorbis --enable-libogg --enable-a52 --enable-dts --enable-libgsm --enable-dc1394 --disable-debug --enable-shared --prefix=/usr 
  libavutil version: 0d.49.0.0
  libavcodec version: 0d.51.11.0
  libavformat version: 0d.50.5.0
  built on Sep 20 2006 00:26:15, gcc: 4.1.2 20060906 (prerelease) (Ubuntu 4.1.1-13ubuntu2)
21.DEA: I/O error occured
Usually that means that input file is truncated and/or corrupted.