Video Problems

Yesterday I managed to convert the sound files so that I was able to import them onto Final Cut Pro. Once I had completed the director's commentary for the two minute opening I then exported the film and saved it on my pen drive to upload when I got home. However, when I went to open the film it only played the voice over part and there was no video, even though I made sure that it worked when I was at school. Once I have figured out what went wrong, I will upload the Director's Commentary and the final part of the evaluation onto Blogger.