UI Calendar Demo does not work in IE 7

UI Calendar Demo does not work in IE 7


http://docs.jquery.com/Plugins/Calendar
It works all day long in Firefox 2.0.0.6 but no matter how I click in
the box using IE 7, nothing happens.
At one point on another box I was able to get a javascript exception
but I am not able to reproduce this behavior at home.
Joe