Jaush -- the version that is in the "nUI: Core" directory is NOT the one you're looking for. You need the version in the "nUI: nUI+ Core" directory which you cannot see and do not have access to because you have not signed up for the newsletter, the explanation of which and directions for which are both in the link I gave you.
Go to
http://www.nUIaddon.com/plus.html and sign up for the newsletter, then follow the directions in the newsletter to gain access to the nUI+ download area so you can get the correct version.