Hi Norm,
Thanks for the link. My Sony Handycam was Hi8 and Digital8 tape-based, and so here's what I found at the top of the link:
If your camera is tape-based, ensure it is not a Hi-8 or Digital-8 tape. Make sure the footage you recorded is not in Hi-8 format. Some DV cameras may work with Hi-8 footage but iMovie '08 and later does not.
The only issue I have with this … I WAS able to connect the camera to my previous Mac (G5) and its iMovie application (maybe pre-iMovie '08?), and did in fact have the ability to control the camera and import the tape-based clips as movies. I still have that old G5 but I think the iMovie got updated to iMovie '09 and now there's no connectivity.
That's the camera issue. On the application side of things, now I tried re-importing the previous iMovie Projects, and they aren't being seen by even the iMovie '09 anymore.