Newbie Question on Vendor Add

This is my first time making a NetSuite web service call.  I am attempting to add a vendor with the code below.  I get the following error:

You do not have permissions to set a value for element lastname due to one of the following reasons: 1) The field is read-only; 2) An associated feature is disabled; 3) The field is available either when a record is created or updated, but not in both cases.

         VendorAddressbook addressBook = new VendorAddressbook();          addressBook.setAddr1(pParty.getAddr().getStreet());          addressBook.setCity(pParty.getAddr().getCity());          addressBook.setState(getStateCodeFromTwoLetterAbbrev(pParty.getAddr().getState()));          addressBook.setCountry(Country._unitedStates);          addressBook.setZip(pParty.getAddr().getPost());          addressBook.setPhone(pParty.getPhone());            VendorAddressbook[] addressArray = new VendorAddressbook[1];          addressArray[0] = addressBook;          VendorAddressbookList addressList = new VendorAddressbookList(addressArray, true);            // Create the Vendor          Vendor nsVendor = new Vendor();          nsVendor.setExternalId(pParty.getPartyId());          nsVendor.setFirstName(pParty.getFirstName());          nsVendor.setMiddleName(pParty.getMiddleName());          nsVendor.setLastName(pParty.getLastName());          nsVendor.setEmail(pParty.getEmail());          nsVendor.setAddressbookList(addressList);            addRecord(nsVendor);