When trying to download content, why do I constantly get "ADE quit unexpectedly"?

When trying to download an e-book from the library, I go to File, add to Library, click on ACSM, click on the name I want, click Add, then the ADE says Fulfilling.... and Downloading content with the blue progress bar going to the end, BUT then a screen comes up saying "ADE quit unexpectedly" and gives a full page of notes.