Are you sure that your radio streaming service doesn't have an SSL option? If not, you could set up a small proxy server that returned SSL content yourself, but it might be hard to restream the radio audio.
Post any errors that PHP gives you. It's also possible that your server/IP-range has been blacklisted by whoever you're trying to send email to.
Try confirming that the email was sent using a simple if/else statement.
<?php
$from = "[email protected]";
$to = "[email protected]";
$subject =...