OK, I’ve experimented a little more.
If I create a new movie in Flash 8 and export it as SWF maintaining the default settings, QuickTime won’t play it.
If I export it removing the option “Compress movie”, then I can play it in QT and import it into FCP without any problems.
I believe Flash 8 might be the only version that use the option “Compress movie” by default, at least CS3 don’t.
Hope this can help.
Petter Brox