you have removed the captcha and security aquestion form elements, but noit the captcha validation code.
delete the following 2 lines
$WAFV_Errors .= WAValidateLE((strtolower(isset($_POST["Security_Code"])?$_POST["Security_Code"]:"")) . "",((isset($_SESSION["captcha_Security_Code"]))?strtolower($_SESSION["captcha_Security_Code"]):"") . "",true,15);
$WAFV_Errors .= WAValidateLE((strtolower(isset($_POST["Security_Answer"])?$_POST["Security_Answer"]:"")) . "",((isset($_SESSION["random_answer"]))?strtolower($_SESSION["random_answer"]):"") . "",true,16);
for any form elements you remove, you need to remove the validation as well.