iMovie Error (-50) PLEASE HELP!

I'll make this short. I have a movie I made in iMovie, 14 hours, 32 minutes, and 52 seconds long. I'm trying to export it so I can burn it. Instead, it says:

Unable to prepare project for publishing

The project could not be prepared for publishing

because an error occurred. (-50)

I've tried sharing to Media Browser and iDVD, but neither works. I have a MacBook Pro 4,3 with 40.04 GB free, and I use iMovie 09 8.0.6. Why isn't it working? Please, this has been so frustrating, if anyone can help please do.