Can you please elaborate on "audio not loading"? What works and what doesn't? Does the file appear in Express Scribe with the correct time, you just can't hear anything when you play it? Do other files play file with Express Scribe?
Either check that Express Scribe is using the correct audio device to playback, or try converting the file with Switch (although you shouldn't need to do this as Express Scribe natively supports mp3 files...).