Not sure why you can't run the setup - it does require .NET 2.0/3.5 (2.0 is included, but it isn't the Win10 version.) I just download and extracted the file, and ran the setup.exe under the English folder and it installs with no issue and loads the viewer software after install. It gives me a 'no camera attached' error, but that's expected since there is no doc camera attached. It also works from running the SDP-860.exe -> English and then under the USB S/W selecting SDP USB Viewer should also run the installer.
.NET 2.0/3.5 is available here: https://www.microsoft.com/en-us/download/details.aspx?id=21
or through the directions here: https://docs.microsoft.com/en-us/dotnet/framework/install/dotnet-35-windows-10