This is a required prevention measure for not allowing users to enter the keywords section without specifying their Root keyword and/or Landing/Redirection page for the ad group first.

Here is a flash movie on how to setup an Ad Campaign:
http://neoperformancer.com/np-campaign-setup.php

Please specify your Root keyword for the Ad Group.
1.  Select the checkbox of the group.
2.  Enter your Root Keyword in the respective text field
3.  Click Edit

Specify Landing Page for the Ad Group:
4.  Select the checkbox of the ad group.
5.  Enter your full Landing page URL in the respective text field
6.  Click Edit

Then you can view keywords section.

Please also address to the “How It Works” webpage at
http://neoperformancer.com/how-it-works.php