Since the page is being redirected to ht e thank you page, It means that Universal Has compiled the email and has passed it on to the SMTP server.
If the email is not being received, it means that the SMTP server has refused to relay the email message.
Double check with your host that you are using the Correct SMTP server in the universal Email settings.
you nay also want to make sure that the from address is set to a valid email address for your hosting domain. Some SMTP servers will refuse to relay the email if the from address is not a valid address for your domain.
On the email settings you may also need to check the option to Include the from address as an extra parameter.
as for the error you are getting, the webassist/email/waue_contact_usbb_1.php file is not intended to be accessed directly. when UE is applied to your form page, a require_once line is added to attach the webassist/email/mail_php.php which defines the waue_definition() function.