Error: Can't instantiate class NHapi.Model.V21.Datatype.CM
(System.NullReferenceException): Object reference not set to an instance of an object.: Segment: ORC (rep 0) Field #2

Test Message:
MSH|^~&|HIS|MedCenter|LIS|MedCenter|20060307110114||ORM^O01|MSGID20060307110114|P|2.1
PID|||12001||Jones^John^^^Mr.||19670824|M|||123 West St.^^Denver^CO^80020^USA|||||||
PV1||O|OP^PAREG^||||2342^Jones^Bob|||OP|||||||||2|||||||||||||||||||||||||20060307110111|
ORC|NW|20060307110114
OBR|1|20060307110114||003038^Urinalysis^L|||20060307110114