Error Opening Asset

Unable to convert XML to AAF. Clips come from Sony a7S. Have exported previous XML projects and had no trouble converting. Error is as follows:

Writing AAF file
Adding assets to AAF file
Adding essence for asset [C0028] to AAF file
Opening audio extractor for portion 0 of asset [C0028]
Failed to open audio extractor
Error Opening asset (/Volumes/G-DRIVE/Coffee - Main.fcpbundle/3-17-16/Original Media/C0028 (fcp1).mp4) with QuickTime (A necessary data reference could not be resolved.) [-2000] []

Suggestion: Please ensure that:
- the media file has not been moved or deleted;
- you have added its location to the Media Locations in preferences;
- the media file can be played using QuickTime player.

No AAF file has been generated.