Sometimes the calendar does not load --- and you get an error message. This is because its a free calendar service. Usually if you hit your reload button, it refreshes properly. Occasionally its necessary to hit the reload 3-4 times before it appears. This problem might appear on any page of the calendar (the popup with directions or the signup form). In all cases, just reload until it appears. Sorry for the inconvenience.
If you get a message that says calendar contains no data, click the link again -- it does contain data.