change line 15:
$WAFV_Errors .= WAValidateLE((strtolower(isset($_POST["Security_Code"])?$_POST["Security_Code"]:"")) . "",((isset($_SESSION["captcha_Security_Code"]))?strtolower($_SESSION["captcha_Security_Code"]):"") . "",true,5);
$WAFV_Errors .= WAValidateLE((strtolower(isset($_POST["Security_Code"])?$_POST["Security_Code"]:"")) . "",((isset($_SESSION["captcha_Security_Code_1"]))?strtolower($_SESSION["captcha_Security_Code_1"]):"") . "",true,5);
your original code is comparing to the captcha_Security_Code session variable, but the session is being created as captcha_Security_Code_1