Adobe ID two devices

I have two problems:

1. I downloaded Adobe Digital Editions to my desktop, I didn't sign in with my Adobe ID. Nevertheless I bought, read and I am able to manage my 2 e-books in my desktop. When I try to sign in it doesn't let me because I signed on a tablet. (Second problem)

2. I downloaded Adobe Digital Editions to my tablet, after I have bought and installed all of it in my desktop. I was able to sign in in my tablet but I can't read anything. When I try to open the books I bought it says I can't because it has been opened in another account (which does not exist)

I really need to have this e-books in my tablet.