I have purchased an eBook and I downloaded it and opened it on the application "Adobe Digital Editions" before authorizing my computer on "Adobe Digital Editions" using my Adobe ID; after I authorized my computer, I am not able to open eBook agian, and when I try to download the eBook file again, it gives me a message that the eBook is associated with another user, is there a way to resolve this issue?
I had the same problem and yesterday I spend several hours trying to fix it but nothing happened. Today I found that when you Download a purchased book in Adobe DE in your PC without authotizing to share the book with other devices, the book can be read only in the PC. In order to use other devices I had to create a new Adobe ID with a different login and password and then, authorice the app to access the web site of the vendor. After that, I was able to download the book with the app of the vendor (Bajalibros.com) in my cell phone and my tablet.
I hope this can be a good solution to your problem.