First, they built the original app so that if you so much as moved a folder, your digital editions were rendered useless and you had to go thru long, demeaning harangues with Adobe to get them back.
Then they uncoupled this from Adobe reader, and failed to issue a Mac version for months.
In the Flash versions so far, all my bought and paid for digital editions came up blank.
In this version, they now report actual errors in the PDF files themselves and I'm instructed to go get another copy of each book from the vendor.

Adobe's either going to fix this or reimburse me for the $60 worth of digital books I bought that are no longer readable.