8.2.3 & QT crashing on export

Hey friends, I've digitized some 3/4 inch footage on the fly into m100 4x3 720X486. After assembling in a timeline I try to export as:

Self contained Movie: M100 Crashes sometimes
as a QT file: M100 Crashes
AS a self contained movie from M100 going to H.264 codec in QT, QT crashes.

All files play completely in M100 and I did get a:
QT export failed: The movie contains some invalid data. (-8969)

I've only been succesful in exporting about 25% of my movies.

I'm running 8.2.3a, QT 7.5 and OS 10.4.11

I did have a few dropped video sync errors on import and was using a bottom of the line 3/4" deck. Could these files be corrupted from a weak import signal?

Many thanks for your input!

Kind Regards,
Chris