
I'm happy as a child, such a blast to play!

But... My Radias wasn't recognized by the Sound Editor software either, with this same error. USB interface was fine, oldschool midi interface was also fine (e.g. both able to steer Fruityloops midi), midi driver was properly installed, radias was present in Windows device manager, but still that wretched "device inquiry error". Then I followed the instructions on here and now it works!
Confirmed working on Windows 10 x64.
/edit: Note: Radias firmware and OS updated to latest versions (resp. 1.07 and 2.0 IIRC) - previous owner never did that apparently. Those also worked perfectly fine on Windows 10 x64.
Not exactly sure what exact setting finally did the trick but whatever, it works perfectly now

Important: be sure to restart first your device and then (after it has fully booted) the Sound Editor application on your PC, after you make any changes to anything anywhere. This is what bit me in the a$$, some settings seem to need some reboots.