I'm trying to burn a movie
You need to explain what this means to you because obviously it means something different to others.
What format is "the movie" in?
Do you have a full file set if not an ISO?
Is your aim to make a DVD that will play in a similar fashion to one you would buy, or do you just want to store a movie file as data on the DVD?
A better explanation of what you are trying to achieve, with what exactly is the source, will help others to understand what might be happening.