Ok, my version is the old one, at least what’s registered.
As I didn’t change the proposed installation path ( see Issues with Nik4 - #8 by Wolfgang ) obviously the ‘old’ version overwrote the ‘new’ one.
I guess, before Nik4 everything was working and you might try the same.
( to get rid of it … see Nik Collection 4 - #27 by Wolfgang )