Well, before you go uninstalling and re-installing things, just verify that the CMS is actually turned on! There's a toggle switch at the top of the Content / Smart Content browser, and if you're using DIM to install packages, be sure the one there is on as well.
There's another case where you get a similar message, and that's when you try to view a product in Smart Content, but the product's metadata is corrupt, incomplete, or missing altogether.
As soon as I get a minute, I'll look into the script to see why exactly that message would be triggered.