Try using another player.
VLC media player is the one we recommend, it has the codecs built in and will play most file types.
You may need to d/load some codecs for your player. See:
CODECs list for Movies/Alternate players / Video help forums/ video-mp3 fixers
It could be the video itself. See if you can find another one and check the files with Bitzi before d/loading.
How to use Bitzi Web Lookup