It looks like there are a few syntax errors in your regular expression particularly with what characters need to be escaped in your list of special characters. Try using this instead:
$WAFV_Errors .= WAValidateRX(((isset($_POST["Registration_group_2_Password"]))?$_POST["Registration_group_2_Password"]:"") . "","/^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[*.!@$%^&\(\)\{\}\[\]:;<>,\.\?\/~_+-=\|]/).{8,32}$",true,10);