that is the validation for the security question.
looks like you have removed the security question from the form, but left the validation in place.
delete the following line to remove the security question validation:
$WAFV_Errors .= WAValidateLE((strtolower(isset($_POST["Security_Answer"])?$_POST["Security_Answer"]:"")) . "",((isset($_SESSION["random_answer"]))?strtolower($_SESSION["random_answer"]):"") . "",true,14);