I am running Digital editions version 184.108.40.2065 on Windows 7 Professional. I also have the same version of Digital Editions on my old laptop running Windows XP. I can access my book on the old laptop using Digital Editions. When I try to add the book to my Digital Editions on the Windows 7 computer I get this message:
Cisco_Unity_Deployment_and_.PDF: This document cannot be opened on this machine. Please contact the site where you obtained the document to download another copy.
I don't remember where I bought the book so I cannot download another copy.