Quote - Are you trying to load a material that is to be bought at Cornucopia3d.com? Those items show the cornucopia logo on their preview. They rae for sale at Corn, they are not on your computer.

No - I'm trying to load stuff that is on my computer, doesn't have the little cornucopia symbol on it and is part of the install. Stuff that was working fine before I installed the paid version.

Quote - btw, you could also try to contact customer support if you can't find the solution.

Have you seen their customer support pages?  they have a contact option for if you are unable to install the software then they have some paper trails for other stuff that either lead back to their store or to a link to Cornucopia's forums.
It's a dead end basically.