The Mac OS Setup Assistant does not recognize, and is unable to configure the Color StyleWriter 4000 Series drivers and therefore, the Apple Color StyleWriter 4100 or Color StyleWriter 4500. To configure one of these printers, you will need to do so through the Chooser.
If you use the Mac OS Assistant to configure your computer, after responding to all of Mac OS Setup Assistant questions, quit the assistant and open the Chooser. Then select the Color StyleWriter 4000 Series driver to setup your printer for use on the appropriate serial port.