This means one of two things:
Your security settings don't allow this page to run scripts. (If you're using Internet Explorer, look for a yellow bar at the top of the page. Try clicking there and selecting “Allow Blocked Content...”.)
Or, your browser doesn't support JavaScript at all. (In this case, you should get the free Firefox browser.)
Good luck! If you discover any more good troubleshooting tips, please send them in: jason@jorendorff.com.
Welcome to Try Scheme! Enter some Scheme code in the text box at the bottom of the page. Then hit the scm button to see the result.