I keep getting a message error! check activation when I try to download a book from my library. I downloaded adobe digital 4.0 and then uninstalled it and tried the 3.0 version and I get the error message for each version. How do I activate my account/computer/whatever is needed? Is there actually a phone number to call instead of these forums? I've gone through a few posts and nothing has helped nor have issues been answered by adobe.
I had the same problem that I solved unistalling both that programs (adobe digital 4.0 and digital 3.0), installing than only Adobe Digital Edition 3.0 and now everything work well.
Got the answer from another thread. Erase your authorization (under help tab in library mode) and close program. Re-open and authorize again. Re download or re-open. Worked for me.