Re: Configuring my system

Yup as Shane notes, and as you noted yourself ... everything has to match and what you have there doesn't match at all:

Clip Properties: Frame Size: 1280x720, Compressor: Apple Pro Res 422, Vid Rate: 24fps
Sequence Settings: Frame size 720x480 NTSC DV 3:2, QT Video settings: DV/DVCPRO - NTSC, Editing timebase: 29.97

I'm guessing that you used the default sequence created for you when you cerated your project ie BEFORE you changed the setup ... so the sequence you are using still has the old default settings (DV - NTSC). Follow Shane's advice ... create a new sequence, drop in your source clip and, if asked, answer "YES" when it asks to conform the sequence to match the clip settings.

Cheers
Andy