If you are having issues with audio not transcribing, update your beta versions of Premiere and AME.
Premiere Version 15.0 Build 23 / AME 15.0 Build 21
As Andy has suggested, please try again with the latest version (15.0 beta build 024 is currently available). We believe that this issue was addressed with build 023. If you still run into this issue with build 023+, please let us know.