Solved the problem with the other program. The wav or mp3 files won't work with "stereo" on the recording channel input. Works with a "mono" input. Ironically, I had this issue with earlier versions of ExpressScribe, but not the more recent ones, until version 10.1.
I am having the same problem with a just-purchased version of 10.1. I use another program to create MP3 files and WAV files, and neither work with the v10.1. Did you ever solve your issue? I can create mp3 and wav files using other programs that work.