With the transfer of the database of projects to the new version, some of the links broke! The StarLogo Nova development team is working on a fix as we speak.
Here's a work around for now. Type GUTS in the search bar at the top of your "my projects" page. You should then see a number of Projects - one of them will have GUTS as the creator. Click on the word GUTS and you will get to the top of the GUTS projects tree. (or type http://www.slnova.org/GUTS/) Then click on public projects and you will see the models associated with each module there.