I had a heck of a time trying to find some sort of support on DMXzone.com and when I found a forum it looks to be old and full of spam; however, pulling up their support chat got me instantly to an answer. It must be something with their installer and 3rd party extensions. He pointed me to an updated beta version of their app (link below) and after the install, all extensions appeared to install as expected.
https://www.dmxzone.com/beta/DMXzone-Extension-Manager-Mac-1.2.1-rc1.dmg