convert the movie to aiff. dont use mp3 sound.
i dont do anything special to handle audio files.
i just noticed its unreliable in catalyst.
I think MP3 files dont like to locate to any position in the movie - using in or outpoints. they dont loop well either.

mp3 is a compressed audio format, AIFF is uncompressed.

you can use quicktime player to export an aiff file.

yes you rendered a dv-pal movie at 100x100 - but its still 3.5MB/s data rate - quicktime cheats. it doesnt actually make the movie at 100x100. it fiddles with parameters somewhere.
DV codec only support 720x576 at 25Mbps (megabits/secs) or 3.5MB/s (megabytes/sec)
all the other 620x476 pixels are still in the movie- somewhere.

either of these things may or may not have been responsible for the crash.