I am trying to download library books on my macbook and it is not opening. The screen comes blank when I open the ebook; the sample books here work fine. I had this problem before and somehow it was back to normal but I am having the same problem again. I have a Mac OS X 10.5.8. Please help!!!
It could be an authorization issue; though that should give a clearer error message.
The sample books probably don't not worry about the DRM which is why they are OK.
Try deauthorizing the mac (cmd-shift-D).
Restart ADE and you will be asked to reauthorize. Give it you Adobe id and password.
With luck, all the books will then work.