Hi Nancy -
What video format are you trying to run on you Blackberry?
There are a number of programs on Download.com that will convert your video to a Blackberry specific format, as well as provide you with the appropriate resolution.
You can try Blackberry Video Converter, which is free, and available on Download.com here:
I have a new Storm and used the video function - when I try to playback, it says it's loading, but then states "the media being played is of an unsupported format." What is that?? It shows the files there, but I can't figure this out - any help is greatly appreciated!