With the latest ADE v 126.96.36.199585 when I attempt to add a ACSM file downloaded from Google Books I receive a "Error! Check activation" message. I am able to access other books previously on my computer. When I attempt to deauthorize the computer I get "Unable to Erase Authorization. Please try after some time."
Consequently I am completely able to read my new downloaded book.
Has anyone else had this problem and been able to solve it?