To fix it, I had to getting the driver installation tar from Samsung. I then used "tar xvf ..." on it. Then I did "cd cdroot." I ran autorun until driver select, but it did not come up with the right driver, so I exited then. I copied the right driver manually out as "cp Linux/noarch/at_opt/share/ppd/CLP-510splc.ppd ..." Then I installed it using http://localhost:631/admin, selecting the ppd above. I then noticed error messages from web page on printing that there were no privileges to access the drivers. So I unprotected the directories using "chmod a+rx /usr/share/cups/model/samsung" and "chmod u+w /usr/share/cups/model/samsung/*". The printer now works.
I contacted Samsung support and asked them to ask the software department to fix up the permissions on the driver package. The support drones did not have enough brains to do so. Instead I got back a nonsensical message to fix a nonexisting problem with my printer and my e-mail address was put on SPAM list. I will not buy any more Samsung products ever again.