Cannot export iMovie project

I recently finished a 20 minute long video on iMovie 2008 but was unable to export it, receiving only a message which says "Unable to prepare project for publishing. (error -50)". I have tried exporting the project in different formats, locations and sizes, but all to no avail. I've searched online for help and found out that there is a rogue video in the project which must be deleted in order to export the project. I've done this and the result is still the same. Can some of the Verge users skilled at iMovie and Mac can help me here? Thanks a lot!