Before you launch the course, go to the Tools menu at the top right of the browser window (the gear symbol), then click on "Manage Add-ons". You should see an option for "Shockwave Flash Object" (or an Adobe flash option), click it and then click "Enable" at the bottom right of the window. 

*If you do not see flash listed you may need to set the "Show:" drop down menu at the middle left to "All add-ons".

Close the window and launch the course.