Installing IntelliType for your Mircosoft Confort Keyboard Ergo 4000 on macOS X 10.11 (El Capitan) or later will not work. Microsoft didn't update their driver in a while (since 10.7) and didn't sign the extension as they should have done for it to work with the latest versions of macOS.
You could eventually deactivate the security features, but I don't think it worth taking this risk for a keyboard driver. The keyboard works fine without driver, only missing the "Favorites" buttons.
If you really want to customize the "Favorites" shortcut buttons, ControllerMate seems to be a great driver with a great mapping that makes them easily customizable. It is up-to-date and compatible with macOS 10.14 Mojave.