I'm pretty sure "Cinepak Codec by Radius" should be available on every comptuter unless the user has removed it.
What happens if they try to play the file in media player, do they still get a black screen?
This might be usefull
http://www.virtualdub.org/docs_codecs
It might be worth using;
mpeg - every computer that can run dbpro games is going to be able to play them and it is fairly decent.
wmv (windows media video) - if the codec isn't installed then the user just needs to play the file in media player and it will try and download and install the codec.
it's cool to hate