Can't open ebook

I am attempting to download an ebook from my public library's OverDrive site.

I have installed Adobe Digital Editions 3.0 and authorized my computer with my Adobe ID.

When I go to the website, then I download the book as an EPUB eBook and it comes up in my downloads on my computer. However, when I click on it and try to open it, ADE opens but the book doesn't. Instead, I get a pop-up saying:

Unable to download

Error getting license. License Server Communication Problem:

E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER

Please help!