Windows 10 is fully up to date and i can run your linked file of OctanceBench without any problems, it boots up straight away (it doesnt ask me to download NVIDIA cuDNN).
After installing the OctaneRender Demo 2020.2 (Standalone edition) and opening up the Octane application it asks me to download NVIDIA cuDNN. After i click download nothing happens. When i open the Octane-client application it asks me to do the same (Download NVIDIA cuDNN) but again ...