Hi John,
I have had one other report of problems with the audio export. It
seems that there is something malfunctioning deep inside QuickTime.
I'm not completely sure what trigs the problem. Sometimes it just
works and sometimes it doesn't. It seems that multiple audio fades in
different tracks is less likely to work than a single track of audio
that fades, so a workaround might be to first render an interim movie
of each track with fades and then composite all the mixed tracks and
audio together with constant audio levels.
I'm working on replacing the technology for a future update. Leopard
has new technologies for doing the audio export that should be more
reliable than the old QuickTime method currently used.
Problems with the video transitions are a completely different issue
and new to me. Would you please check if you get any error messages?
You do that by running Console.app in /Application/Utilities.
Thanks for your patience,
Martin