Problem with authorizing ADE 2.0 (Mac OSX)

[Guest]

I am trying to authorize an ADOBE DRM EPUB ebook that I purchased from Kobo, as it has been showing up blank on my Kobo ereader. I downloaded ADE 2.0 as recommended by Kobo, but upon trying to authorize my computer, I get this error message:

Activation Server error - code - E_ADEPT_REQUEST_EXPIRED
Digital Editions encounter an error on the activation server

I am using my iMac, running Mac OSX 10. 5. 8 

I have now spent 3 days trying to figure out HOW to read this book on my ereader, and Kobo wasn't a lot of help. Frustration has begun to set in.

Any help would be greatly appreciated.

I haven't had to do this with any other ebooks I have purchased (and they are all ADOBE DRM EPUB files), so I'm not really sure what I am doing... or why I have to do it with this one.

UPDATED TO ADD:  I assume that the ebook vendor for Kobo is Adobe ID? Or should I be selecting another from the list? Kobo itself isn't in there, but I assume because they use Adobe DRM epub that Adobe ID is the vendor.... Just wondering if this would make a difference in the authorization.

[Guest]

And the authorization worked on my husbands Windows laptop.