[MacDV] Export/import problem

[lloyds]

I'm trying to create a dvd, using iDVD4, from a FCE2 movie.  Six shorter
sequences, ranging in length from  7 to 20 minutes, export from FCE
(using QuickTime Movie) just fine, and play in iDVD preview just fine.
But the "feature" film, 34 minutes long, exports the audio but no video,
although the settings ask for both.  When I play it in QuickTime Player
or import to iDVD, I get the sound but no video image -- a black
screen.  Tried several times.  Any suggestions?

BobLL