I have had maybe 10 out of approx 3000 files which have done this. A reload of the exact same file from my PC fixes the problem. All I can think of is some kind of corruption in the initial transfer.

Did the problem manifest itself only on version 2.0b3 and not on 2.0b7?

If so, then it has nothing to do with corruption. The files were never damaged, it was only a non-working piece of code being applied to the files at playback time.

This was a known bug in 2.0b3 and it was fixed in 2.0b7.

If you are sure you saw this problem happening in 2.0b7 please let us know.