Right, i've figured it out and i don't think it's to do with bit-ness (maybe your other friend had problems with bitness). As stated previously i have windows 10 pro N installed. I did some research and it turns out the N version installs without any media packages. And after digging around in your code i saw it was Naudio that was causing problems (as you've also stated). Looks like it's trying to import a dependency in that WASAPI you're talking about that didn't exist on my PC.
I installed a media pack: https://www.microsoft.com/en-us/download/confirmation.aspx?id=53356
Which has now fixed the issue. I think you might want to put a link to that in a FAQ for any other people who come accross this. I don't know if it's also worth reporting to the NAudio guys? Would be good to add some startup check to check it's installed...
Thanks again for your help and the tool is great. On a side note, i saw you're looking for help and was thinking i could lend a hand. I'll PM you.
Hallux,