It is hard for me to tell from you screen shot, but is there nothing when you click on the Red Check button? If you click on it and there is an error, they will be displayed at the bottom of your screen.
Screenshot from my App:
Then what I think you did was got ahead and already added the Entity to the overview pages
Jason – don’t know if you are still hung up on this. I went thru the RAD course and at the same place as you, I followed the directions exactly and when I clicked on Preview, i didn’t get errors either. I should have because I didn’t have the entity or page like I should have. I just continued on with the exercise and did Error 1 and 2 like I had them.