Password problem

I've been using Adobe Digital Editions as an e-reader on my iPad, by dragging books the app via iTunes.

I just bought a book from Kobo, and since I don't care for the Kobo e-reader for my iPad (It doesn't allow me to look up stuff on the Internet), I download the book as:

URLLink.acm.

When I click on that, I see that I have options to open it with one of the following:

Adobe Digital Editions 4.5 app

Reader Library.app

Reader.app

With the Adobe app, I get:

Error getting License. License Server Communication Problem:

E_ACT_NOT_READY

I get other errors with the other apps.

I see that my Digital Editions app on my Mac has the option to erase authorization, but when I tried it, I got:

"Unable to Erase Authorization.   Please try after some time".

I tried again after some time.   I'm not sure I got the right password.   I think I have one for this web page and another for my reading.