ZF1主键列不是此表中的列

I get error when i try list users in Zend Framework 1:

Primary key column(s) (id) are not columns in this table ()"

Controller :

public function listAction(){

    $mapper = new Application_Model_UserMapper();
    $users = $mapper->fetchAll();

Mapper :

public function fetchAll($where=null)
{

    $resultSet = $this->getDbTable()->fetchAll($where);

    return $resultSet;

dbtable

class Application_Model_DbTable_User extends Zend_Db_Table_Abstract {

    protected $name = 'users';

    protected $_primary ='id';

}

Model

class Application_Model_User {

    protected $_id;
    protected $_useremail;
    protected $_usergroup;
    protected $_password;
    protected $_password_salt;

Sql :

CREATE TABLE users (
    id INTEGER  NOT NULL PRIMARY KEY AUTOINCREMENT,
    useremail VARCHAR(50) UNIQUE NOT NULL,
    password VARCHAR(32) NULL,
    password_salt VARCHAR(32) NULL,
    usergroup VARCHAR(12) NULL,
    real_name VARCHAR(150) NULL
);
CREATE INDEX "idUser" ON "users" ("useremail");