E_ADEPT_DOCUMENT_TOO_SHORT

Good morning,
I have tried using Adobe Digital Editions 3.0, 4.5, and 4.5.11, authorizing my computer with and without an Adobe ID, and deleting the registry key.

None of these methods change the outcome of getting an E_ADEPT_DOCUMENT_TOO_SHORT error message when trying to download a book. Adobe "help" desk just sends me to this forum and refuses to provide any solutions as "ADE has been discontinued."