Some nook users (and other users) have found that their device does not show up correctly on ADE2.0.
Using the more reliable 1.7.2 has helped in many (not all) cases.
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
The forum software is sometimes corrupting the link above. There shouldn't be a blank in 'editio ns.html'. The following redirects to the same page: http://tinyurl.com/diged172