Google Analyticator is a must have for every WordPress Website. It handles the integration with Google Analytics and makes it easy to view website trends.
If you are wondering why the graph is not populating it is because you have not successfully registered your domain with the Google account being used.
The solution can be found in the WordPress Forums. The trick is to go to Google Accounts | Manage your Domains and add your domain to the google account that is connected to the google analytics. Once added, manage registration and add the domain name and update the OAuth. You do not have to set up anything complicated, though it can be intimidating. This is only because it has potentially additional functionality that you do not need to utilize.