You want to uninstall ADE 4.5 and install ADE 2.0.1. The reason being is that any version ADE past 2.0,1 incudes a new version of DRM that cannot be removed. With ADE 2.0.1 as long as your nook is DRM registered, you could use that PDF on it. Depending which nook you have, the PDF may not be a good experience.
If you get ADE 2.0.1 and dump ADE 4.5, you can go to
https://apprenticealf.wordpress.com/ and get the software needed to remove the DRM and you can get help on using the software if you want/need help.