In order to begin your questionnaire, you must allow Take the Interview access to your webcam and microphone. The "Allow" button should appear in the black box at the setup step.
If the "Allow" button does not appear in the space above, there may be an issue with your version of Adobe Flash. The easiest way to resolve this is to switch to the Google Chrome web browser. Google Chrome automatically updates your Flash Player, which minimizes the possibility of encountering Flash-related issues. You can download it here: https://www.google.com/chrome/
If you are already using Google Chrome, try restarting it. This will trigger an automatic Flash Player update.