lines 3 - 4 are causing the problems:
<?php require_once("webassist/form_validations/wavt_scripts_php.php"); ?>
<?php require_once("webassist/form_validations/wavt_validatedform_php.php"); ?>
null
undefined
<?php require_once("webassist/email/mail_php.php"); ?>
change that to:
<?php require_once("webassist/form_validations/wavt_scripts_php.php"); ?>
<?php require_once("webassist/form_validations/wavt_validatedform_php.php"); ?>
<?php require_once("webassist/email/mail_php.php"); ?>