There actually is no VALUE property for the Date Picker control. You must instead reference the DAY, MONTH, and YEAR properties individually.
Be aware that this can also cause problems when you try to set the date to something, as you must set each property one at a time as well. For example, if you try to set the date to 6/30/2001, you might get an error depending on whether you set the month or day first. If you try to set the day first, and the control's current MONTH is February, you will get an Invalid Date error (date cannot be 2/30/2001). If you try to set the month first, and the control's current date is the 31st, you will also get an Invalid Date error (date cannot be 6/31/2001). What I always do to work around this is set the Day to 1, then set the Month, the Day, and the Year.