Moved to Adobe Digital Editions.
Adobe Digital Editions does not work on an iPad. You need sometihng like the BlueFire Reader or OverDrive. I believe you can manage your Digital Books using Adobe Digital Editions on your Mac.
You can't run Digital Editions on iPad.
Try the Bluefire app; that will read Adobe DRM books.
Overdrive app will also interact with your library, but seems not to work right for some people (including me).