Joe, this is how I responded to this info in the Adobe forum.
Yes, I think I bumped into this when I first got my HP Z820. Suddenly I could not export QT H.264 from any Adobe app or MPEG Streamclip. I did a comeplete reinstall of Win7 and all the apps thinking maybe a Win update or plug in install had screwed things up. Even got Eric from ADK involved in 2 days of trouble shooting. I never did resolve what was causing the problem. This sounds like it was the culprit. Too bad I didnt stumlbe across this post last September : /
Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com
https://www.youtube.com/watch?v=DxPrG3WUyz8
(Best viewed at 1080P and full screen)
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid