The configuration seems to be ok.
It would be a good idea to review if the folder ‘phpMailer/phpmailer.php’ matches with the code in the file ‘contact.php’, in the line 4.
I have made tests with your contact form, and when I filled all the fields, I got the next error:
Invalid address: TO_EMAILYou must provide at least one recipient email address.
This problem is about the variable ‘TO_EMAIL’ in the file config.php