Unknown command in Civil 3D 2023


I recently installed Civil 3D 2023. I am trying to get M-Color to work but have been unsuccessful. I downloaded and installed M-Color_eng_9_9_576_0.msi. I ran "Add M-Color to new AutoCAD installation". The ribbon menu did not display. I opened Civil 3D and checked CUILOAD. There was no M-Color CUI to unload. I then tried running MCO_MCOLOR_MENU but it is an unknown command. I tried 3 different MCO commands and all were "unknown". My guess is the path to M-Color needs to be added to the AutoCAD search path. Did I miss a step that would add the path? How can I get M-Color working with Civil 3D 2023?

Thanks - Jeff