Unable to access an error message corresponding to your field name pan_number.(panVal

I have googled and tried to fix this problem.
1> Auto loaded security
2> Not using xss_clean
3> Callback Function is :

Code:

function dayValidation($dayVaue) {
$day_regex = "/^(0[1-9]|[12][0-9]|3[01])$/";
/* return preg_match($day_regex, $dayVaue); */
if (!preg_match($day_regex, $dayVaue)) {
$this->form_validation->set_message('dayValidation', 'Invalid Date');
return false; // invalid day
} else {
return true;
}
}

4> In application/language/english put the file : MY_form_validation_lang.php with error messages
5> in application/libraries/ put file : MY_form_validation.php with

PHP Code:

public $CI;
public function __construct($rules = array()) {
parent::__construct($rules);
$this->CI->lang->load('MY_form_validation');
} 


PHP Code:

function run($module = '', $group = '') {
    (is_object($module)) AND $this->CI = &$module;
    return parent::run($group);
} 


And still the error is coming. Dont know whats going on. Please help