bawldiggle, Kobo does not recommend using Adobe Digital Editions 2.0.
Instead, use the version of Adobe Digital Editions that Kobo provides:
http://www.kobobooks.com/ade
This is version 1.7.2. You'll find that it lets you choose the Kobo bookstore as one of the providers when you install (you can't do that with 2.0). With that set up, the process of downloading the Adobe DRM ePub files is very simple.
More info is here on the Kobo site:
http://www.kobobooks.com/ade
All best wishes.