Segments are black with missing frames and audio after render

I created a 55 minute show with over 300 files. I used FM4.4.4. Some segments of this presentation were created on prior versions of FM. After rendering as a ProRes file and looking at it in QT, I discovered missing frames and audio, just black and silence. I tried re-rendering as a DVD file and the process froze at 2 minutes to finish. Lots of wasted time and effort. A useful solution would be really helpful. I see others experiencing similar problems. It seems each release of FM brings a new host of problems, along with correction of others. Very discouraging.

Are the black images in another format than the others? We just discovered an issue with Canon RAW files. If not, is it possible to upload and send us the slideshow (to so we can take a closer look?