I'm a ways off from upgrading the event_calendar module to use the DOM. I'd like to let it sit in a somewhat stable state for a while before messing with it. Since you're the only one reporting the bug, I'd really like to focus on why you might be experiencing it.
Can you do me a favor and create another DataObject with a date that uses a tablefield? Make it have nothing to do with the event calendar. Create a new page type, give it a $has_many with the new dataobject, and obviously, make the date editable with a CalendarDateField. Let me know if it blows up.
You're not using a Mac, are you? If so I could screen share with you.
If not I'm open to any other screen sharing service you're aware of to troubleshoot.
My m8 has let me host a default ss site with your calendar module so i can show you what is happening with the date picker, if you could have a look at it that would be great http://www.paulalanrichards.com/ss/
Sorry to report this, but I tested on IE, FF/Win, FF/Mac, and Safari, and I can't get the bug you're describing. I clicked on CalendarEvent, Dates and Times, and clicked a datepicker to edit the date. I get a calendar popup that I am able to click and change the date. It's not the prettiest thing in the world due to the new TableField CSS, but it does nonetheless work. Attached is a screenshot of FF/Mac.
I dont think i explained the issue i am having correctly, its not the calendar on the admin side of the site that has the problem it the one on the front end, when you select a date to view an event for example the 27/02/09 it says.
The requested URL /calendar/2009-02-27 was not found on this server.