You forget to correctly init data in the node:
Incorrect - data for the third cell are not defined
Dim colvalue As Object() = New Object() {"15/10/2005", New DateTime(2005, 10, 15)}
Correct:
Dim colvalue As Object() = New Object() {"15/10/2005", New DateTime(2005, 10, 15), "Data to display in DynamicallyAutoDetectDataTypeColumn cells"}