Twitomatic Automatic Post Generator Plugin Blog to Twitter No Available

Hi. I purchased this plugin Twitomatic Automatic Post Generator with the specific purpose of generating tweets when a new post of published. When I click on Blog -> Twitter I was expecting to see a new page with contorls for setting that feature up. But instead all I get is a largely blank page with the following text:

Sorry, you are not allowed to access this page.

You can see the screenshots. Why isn't the plugin working?