You can remove that line Dreamweaver is complaining about, but also change line 25:
$WAFV_Errors .= WAValidateLE(((isset($_POST["Security_code"]))?strtolower($_POST["Security_question"]):"") . "",((isset($_SESSION["random_answer"]))?$_SESSION["random_answer"]:"") . "",true,5);
to:
$WAFV_Errors .= WAValidateLE(((isset($_POST["Security_question"]))?strtolower($_POST["Security_question"]):"") . "",((isset($_SESSION["random_answer"]))?$_SESSION["random_answer"]:"") . "",true,5);