почему не работает добавление БД?

public static void AddPersonToDatabase(TablePerson Person)
{
objDataContext = new UniverDataContext(connString);
objDataContext.Person.InsertOnSubmit(Person);
objDataContext.SubmitChanges();
}
public static int AddPerson(string name,DateTime birthday, decimal tax, string city, string zip,string address)
{
try
{
TablePerson Person = new TablePerson();
Person.name = name;
Person.birthday = birthday;
Person.address = address;
Person.city = city;
Person.tax = tax;
Person.zip = zip;
AddPersonToDatabase(Person);
}
catch (Exception e) { throw e; }
return 0;
}
сервер присылает ошибку Cannot insert explicit value for identity column in table 'qualref' when IDENTITY_INSERT is set to OFF.
пользуюсь sql 2000