the action of the form is set to use a session variable:
<form class="Basic_Default" id="SimpleContact_Basic_Default" name="SimpleContact_Basic_Default" method="post" action="<?php echo(isset($_SESSION["waue_contact_1_Log"])?$_SESSION["waue_contact_1_Log"]:""); ?>">
change the form tag code to:
<?php echo (htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES)); ?>
<form class="Basic_Default" id="SimpleContact_Basic_Default" name="SimpleContact_Basic_Default" method="post" action="<?php echo (htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES)); ?>">