I am using Windows 8 Single Language (not sure what this means to be honest). The weird thing is though, that after I initially posted this, I tried installing NAV on a brand new laptop running Windows 8 Pro (before any AV, Office or other 3rd Party apps were installed) and it pops up exactly the same error message. I also tried installing it from the install set on the server (so over the network) as well as locally on the machine with the same result.
The idea of this not working on the Single Language machine does make sense as I'd imagine that this is a "Basic/Home" edition of Windows. But why not on the notebook running Pro?