Originally Posted by PeterT
To my mind, this sounds like a corrupted database on the Kobo. Try a logout / login from the Settings | Account menu. This will have the unfortunate side-effects of removing all books from the database and making you go through the setup process again.
You can partially make it less painful by before hand, saving the .adobe-digital-editions to your PC and then, after the setup, copying the two files in it back to your Kobo. This will alleviate the need to redo the ADE authorization.
That fixed everything! Thanks so much!