warning message Javascript Application - 0 elements!

warning message Javascript Application - 0 elements!

I am using your tutorial and keep getting a warning message Javascript Application - 0 elements!
Below is my code.
I am using Windows 7 and mt browser is firefox.

Thanks for your help

Tony Prodger

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
  <title>Hello jQuery world!</title>
  <script type="text/javascript" src="jquery-1.4.2.js"></script>
  <script type="text/javascript" src="script.js">
$('#date').datepicker({showOn: 'button',
buttonText: 'Choose a date',
buttonImage: 'calendar.png',
buttonImageOnly: true,
numberOfMonths: 2,
maxDate: '0d',
minDate: '-1m -1w',
showButtonPanel: true
});
  </script>
</head>
<body>
<a href="">Link</a>
</body>
</html>