Your button has ‘Create Object’ set to yes. This means that the clicking the button will do two things: Create an object of entity Course and show this object Course on the page you chose: Course_Overview. But that page has no page parameter for Course, but only a Datagrid that wants to show a list of Courses.
If your goal is to show one new Course and be able to edit its details: Solve this by selecting page Course_NewEdit instead.
If your goal is to show the list of Courses that are currently in your application: Solve this by switching “Create object” off