I just want to add that I've had exactly this problem, too, a day later.
With ADE 1.71 I can download the Alice In Wonderland and Huckleberry Finn samples -- but cannot download My Antonia, or Sherlock Holmes.
For these, ADE downloaded a URLLink.acsm file, but did not download or open the book. Also, there ADE gave no error -- simply nothing happened!! (I eventually found the URLLink.acsm file deep in the bowels of my file system, but it's uselesss.)
(Is it because some are newer samples, and others are older samples?)
I was going to download an ebook from Wiley Press, but their test sample had exactly the same problem, and I did not want to order a $100+ book and not have ADE open it.
So I just abandoned ADE.
As others have said, this will become a huge business problem for Adobe and their partners, especially since ADE does not have a User Interface that gives a even rudimentary error or status message.
I am another one suffering the same problem: just a few demo books downloaded and now I can download not a single one more. Digital Editions opens if it's closed when I download the ascm file, but it does nothing, just stays silent (how helpful!), and ignores any subsequent books I try to download. No way I would risk to buy a book with this happening!
I found a workaround in this thread: http://forums.adobe.com/thread/445354
I have to download instead of directy opening the ascm files, but the downloads work. This blocking "feature" of Vista is something I hadn't seen seen before, I had no info about it. It's very cumbersome to have to unblock the files one by one, but al least I didn't have to rename them.
Well, I also read the threat you mentioned but unfortunately it doesn't work for me. I have a mac computer ....... But anyway thanks ....
A year later than the rest of the posts and I am having the exact same problem with the Adobe books and with ePub books from my local library. I cannot seem to find any answers at this website. The techie at my local library is trying to help. So far no solution. Any solutions out there? Do the Adobe people read these posts? Thanks
Even later in time: Same problem, except I have not gotten a single book to download from "sample
I had same prob with a new nook. was using firefox and changed to chrome and works like a charm although i am getting books from google(mostly free)