PHP expects sendmail(8) to be running on the local system. I'd ask the system administrator if it is, for starters. If this is a "web host" service, you can try reading their docs/help system for starters, or call them, or maybe they've got online chat.
Anakdote has a good idea as well. Forget about MIME and headers, try a basic mail call first. And I'd test the return value as well:
$success=mail($email, "Test Email", "Test", "From: $from");
(if !$success) {
echo "Sending mail failed!";
}