I downloaded the installer again from your website, and although it is still listed as 2.5.0, when you unzip the folder it is named differently from the one you are directed to when you first purchase the plug in.
The one I was allowed to download straight after purchase is called "H3000-Factory-2.5.0-windows-installer" – this is the one that's not working.
The one I downloaded today off the website is called "H3000Factory250win" – this one works!
The files inside the folders both appear to be the same (same file name and date) so not sure if they're actually any different?
Anyway it's working now and I'm up and running. Thanks for your help!