Here's the steps I did:
Downloaded the app Tradebit and authorized with adobe id. no problems.
Draged the EPUB library file to the tablet.
When trying to open the book, I get an error message to check the adobe id.
Both the tablet and computer use the same id.
Help... I bought the tablet to replace my nook which is starting to give problems and I borrow lots of ebooks.
I don't know the Tradebit app, but try Bluefire reader app and see if it behaves any better.