I'm also having trouble installing drivers and running DRSOsc program on another computer running Windows 8.
The issue with the driver is that it's not digitally signed.
The issue with the DRSOsc is that it's failing to find libusb0.dll. libusb-win32 seemed to have installed upon DRS4 software install, however the supplied version is Windows 7/8 incompatible, so on Windows 7 computer I had to download libusb_win32 v184.108.40.206 from the official website and install it directly, then everything worked fine. However in Windows 8, I am unable to install libusb-win32 because in libusb-win32 Inf Wizard installation program when you select for which device the libusb should be used, it asks to install a driver, but when I point to DRS' driver, it says "Unknown Error: 1" and that's that. One way around the libusb issue is to copy the required dll and sys file directly where the .exe is stored.
I will attempt to disable signed driver signature requirement, and see if the driver installs then, but this should really be fixed instead.
Did you have any progress with that? Unfortunately I don't have a Windows 8 machine here at our institute, so I cannot reproduce your problem. At least I put the 1.2.6 libusb driver into the V5 software package.