Is tis using server side validation?
in the webassist/form_validations/wavt_scripts_php.php fiile
the following line sets the Known TLDs for email address validation:
$knownDomsPat = "/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum|cat|\w{2,2})$/";
you an add additional TLDs to the that line