Yup. I'm betting one of two things: you didn't follow the sequence that
hooks up the Nook first and then ADE; or your Nook isn't registered with
Since you haven't said whether or not you've been using the Nook for a
while, let me start at the beginning. I'll assume a Windows environment as
well. MAC's are similar conceptually, but you'd use different keys and
I'm going to assume that you went to the Adobe website and registered
there. You will have created an Adobe ID and password. Then, you
downloaded and installed ADE on your computer.
You need to register your Nook with B&N, using your Adobe ID and password.
When those steps are completed, you need to make sure that your computer
sees the Nook and has assigned it a drive letter. You can use Windows
Explorer or Control Panel to do this.
When the Nook is 'seen' by your computer, you can start ADE. Your Nook
should be authorized automagically by ADE and appear on the bookshelves
(left hand panel of ADE's Library View).
Hopefully, this will 'fix' your problem. If not, give us more information
and we'll do what we can.