a problem in downloading a DRM pdf file.

Hi,

Today I purchased an ebook via Kobo's site:

http://www.kobobooks.com/ebook/Applied-Natural-Language-Processing-Identification/book-dR0XnmDKKk27gMjojat8DQ/page1.html

It is in my library and when I go to ADOBE DRM PDF in order to download it and read it in Adobe Digital Editions (windows 8 pro) it says that:

"Retailer not authorized" and "The requested eBook title cannot be downloaded at this time due to difficulty in communicating with the retail site. Please try again later."

Kobo's customer services told me to refer to Adobe Digital Editions.

So, is there any solution?

I need your help urgently.

Thanks so much in advance.

Regards.