Thanks for your suggestions. I now have the answer to the problem. After three hours, (a lot of waiting on the phone time), and three levels of Apple experts looking at my computer, we came up with the solution.
It had nothing to do with exporting options from AE. It turns out my original Animation output was fine and the correct format for Final Cut. Final Cut automatically creates the ProRes 422 file when it imports it.
The problem was that my client’s Final Cut X application had somehow switched from importing and showing the original file. It was importing and showing the proxy file. It had also switched off automatic rendering. All we had to do was change the application preferences and it worked fine.
Lesson learned: Always check and recheck the preferences. Don’t import both original and proxy documents unless you have a really big, project. The client was importing both.
Hope this has helped other that may have experienced this problem and thanks for your help.
Sincerely,
Mari