Creating Contact with Primary contact role in a customer

Hi All,

We are trying to create a contact with role as primary contact in a customer.
we are trying with the following code. But it is giving error as
"Missing or Invalid RecordType for AttachTo"

RecordRef contactRole = new RecordRef();
contactRole.internalId = "-10";
contactRole.type =RecordType.contactRole;

RecordRef contact = new RecordRef();
contact.internalId ="1195";
contact.type = RecordType.contact;

RecordRef attachTo = new RecordRef();
attachTo.internalId ="1194";
attachTo.type = RecordType.customer;

AttachContactReference attachReference = new AttachContactReference();
attachReference.attachTo = attachTo;
attachReference.contact =contact;
attachReference.contactRole =contactRole;

WriteResponse res = cnw.attach(attachReference);

Can you pls help me out ...we are importing customers with contacts to our production .so we need to resolve this issue assp.