I have a form with two DateTimePicker fields. In FireFox they work as expected, but in IE7 if you click in the field and choose a date you get a validation error. However if you refresh the page but this time click on the calendar icon and choose the same date, no error message.
http://www.baysideburnie.com/component/chronocontact/?chronoformname=bookings
http://www.baysideburnie.com/component/chronocontact/?chronoformname=bookings