Something wrong with my Quicktime Player or is it my videos?

Last month I’ve been to a video workshop and I have made a few videos. Now these videos that I made I received them back on a disk, now that I try to play it on my laptop it’s not going. Quicktime player opens but I only see a blank/black screen but I do hear the sound. What’s wrong? It is the Quicktime or is it my video?

Oh yea, when I tried to play the video the first time it said something about Quicktime needs something of playback something like that I can’t really remember what.