>At a guess I'd try declaring loDocumentDates.dtDocumentDate as a nullable type and just not setting it if loRow("CloseDate") contains an empty date.....
When doing so, we get:
Server was unable to process request. ---> SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.
So, they are validating. My guess is that even if we go low level, this won't work as we would probably obtain the same.