"The movie contains an incorrect time value"

I get this error message when I'm trying to use Quicktime Pro to crop videos to 720p after I tell it to save the video file as a self-contained movie. I tried using MPEG Streamclip to "Fix All TimeCode Breaks" and then I'd export the video as an MP4 but at that point it would also report an error stating that it's "unable to prepare the video file." I'm just trying to fix the incorrect time value so I can use QuickTime Pro to convert the resolution suitable for the widescreen 16X9 format. Can this be done?