But then, by chance, on my Mac, instead of picking "IP protocol" I picked "Socket/HP Direct", and it worked! So far, things are good. I can now print to this printer over the Ethernet to a TCP/IP address with no problems and gain access to all features.
My presets for my Hewlett Packard got screwed up, though, and I had to reinitialize them. Still in the process of straightening them out. It seems that presets are shared across printers, so if you have a preset which is for a specific printer (like picking a specific tray) name it for that printer!
Remember to install the MacOSX drivers, which, though a bit out of date and for 10.3.2, are available at the Samsung website. You should be able to pick the printer model "Samsung CLP-500", from the printer model popup from the Printer Setup Utility.

