From the readme:

1. To use Sputnik you must install lastest MUI beta (http://www.stuntz.com/muibeta_20060922.lha)
and some upto date Ambient (http://www.ambient-desktop.com). You may want also to copy
Libs and Prefs dirs to your SYS: catalog. If you have in Libs: z.library you must delete it -
MUI4 might crash if that library is there.

.. I downloaded the archive just for the readme. :)