Adobe digital editions shuts down

I am working on a Mac. I bought an ebook (epub) recently and every time I try to open it, ADE shuts down unexpectedly. The book cost me 40 dollars, I would like to read it! I uninstalled and reinstalled several times, but no good.

I tried opening it on my iPad with bluefire reader, but there I get the message that the book was already downloaded with another account. I try to put in username and password, but that doesn't seem to work either. First ebook experience not going great!

Than you for your help!