I have the same problem as Dorie Roa.
I purchased a book from Weltbild.de. They told me, I first have to download Adobe Digital Editions and gave me the link. I followed the link and clicked on "download now". It also goes to a box "Launch" ("Starten" in German) instead of "Install".
Clicking on "Launch" opens a small window asking me for the administrator-password. I entered it, a new windowopens telling me, I have not the rights. But even as Administrator I have not the rights - I tried it.
Don't know what else I can do to download Adobe Digital Editions.
My operating system: Windows7
My web browser: Mozilla Firefox (tried Internet Explorer, too)
This wasn't helpful to me, 'cause my problem is not listed or answered: http://helpx.adobe.com/digital-editions/kb/cant-install-digital-editio ns.html
Hope you can help me.