Yeah, same problem here. And, if I install the demo on a networked PC (Windows 10), I get no sound at all. Yes, all the settings are right. Works on the FSX PC.
Anyway, this looks like a very good add-on with, at last better sounding voices. Too bad the steep price tag stops me from buying it at once, so guess I'll keep an eye on where this is going. Keep up the good work!