"Unable to prepare project for publishing" Error

Hi. I created a short film using iMovie and published it to iTunes using the medium size setting. This worked fine. I was able to watch the film in iTunes and sync it to my iPod Touch.

I then added some title frames to the film and tried to re-publish it to iTunes. Now I am getting this error: "Unable to prepare project for publishing. The project could not be prepared for publishing because an error occurred. (Code revision is wrong)".

Does anyone know what this error means and how to resolve it?

Thank you