The component of Icare that talks to the USI Web Services requires .NET Framework 4 or 4.5 installed on your computer.
This is already installed on Windows 10 but may need to be installed on older PCs.
If you are only installing on a single PC then use:
Windows (x86, 32-bit and 64-bit), Web Installer
If you are installing on a couple of PCs the use:
Windows (x86, 32-bit and 64-bit), Full Installer