how to set only one error message for email id in zend 1

Question

here is my email form :

$this->addElement('text', 'Email', array(
        'label'      => 'Email address:',
        'required'   => true,
        'filters'    => array('StringTrim'),
        'validators' => array(
            'EmailAddress',
             array('Db_NoRecordExists', true, array(
                    'table' => 'users', 
                    'field' => 'email',
                    'messages' => array(
                        'recordFound' => 'Email already taken',

                    )
                )
            )
      )));

Output :Here is the many error message i am getting