Apple can't help because it is not a QT problem. Read back a few hundred posts and you will see a common problem -
Number 1: "my [insert unknown codec here] AVI [usually it is AVI] won't play back on QT".
Number 2: "why won't Apple make QT encode [insert codec here including MPEG-1 and 2] my format I want?" (or for MPEG-1/2 export QT from muxed audio, same idea)
Because they are promoting Quicktime and their formats. Why won't people harp about Windows Media Player or their encoder not making MPEG-4 or H264 files? Because Microsoft wants people to make WMV files or even better, adopt it as a defacto standard.
I think the starting point for these tiny little digital camera movies should be an effort by the camera makers to stick to a format that is cross-platform, and some do, e.g. MJPEG in QT which are fine on Apple and Windows.
But AVI, with specific no codec listed and ulaw audio compression seems like finding a cheap way to make videos ot a good way to make videos.
It is not an Apple software or Applecare problem. You cannot fix what is not broken, I hope that is clearer.
This Perian freebie is a start though I haven't tested it - I have it but I don't have any non-compliant videos to test.
One final thought - 99% of users want to PLAY these files. They then fixate on tweaking QT to do that when often VLC will do it without a tweak.
If playing is the desired outcome, get a different player.
I know iPhoto supposedly prints, no idea if it does that well or poorly. I use Photoshop because it is an application that is better suited to my needs. If I get a wonky AVI file I will start with VLC first.