[eluser]Zaher Ghaibeh[/eluser]
you have to extend the form_validation class to overwrite the validations rules that you use to accept your FR chars.
and i think those problems can be found in a validations rules like alpha , alpha_num ... etc ..
Code:
function alpha($str)
{
return ( ! preg_match("/^([a-z])+$/i", $str)) ? FALSE : TRUE;
}