Can't open books downloaded from library

[AnyaPA]

I can no longer download from my library.  The book appears on my computer, but when I try to open it, this is the message I get:

This just started happening.  I tried downloading another book, and got the same message.

Now, every time I open Adobe, I get another message that a download has not completed, but when I try to complete it, this message comes up again.