Using getSelectValue to get all employee Departments

I am using the following code to get all departments for employees:

GetSelectValueFieldDescription fieldDesc = new GetSelectValueFieldDescription();
fieldDesc.setRecordType(RecordType.employee);
fieldDesc.setField("department");
GetSelectValueResult result = _port.getSelectValue(fieldDescription,1);

Interestingly, this code works fine on my dev instance and successfully pulls all the departments but returns the following error on a client's sandbox instance.
"Results are incomplete. You must provide a value for field subsidiary."
I am new to NetSuite integration and don't know what to make of this error. Would be great if someone here could guide me.

Thanks,
SNQ