I knew how to add my favorite screensaver, Skyrocket, to Xubuntu based on having researched it before: http://www.lueckdatasystems.com/Adding_back_Skyrocket_screen_saver_to_Ub... However this time, the Really Slick Screensavers GLX Port entries did not show up in the list of screensavers. So I went searching how to get them to become available.
I discovered in this file:
that I should perform the following:
Then when entering the screensaver configuration panel, I am warned that xscreensaver is currently not running, would I like to start it, (yes), and Skyrocket is in the list of screensavers.