Access-Control-Allow-Origin header missing?

From:	rkevinburton at charter dot net	Date:	Fri, 24 Jan 2014 20:00:46 +0000
Subject:	Access-Control-Allow-Origin header missing?
Groups:	php.general
Request:	Send a blank email to php-general+get-322749@lists.php.net to get a copy of this message

I have the following code to add the appropriate header then redirect but I am still getting an error that this header is missing. What am I doing wrong?

        header("HTTP/1.1 301 Moved Permanently");
        header("Access-Control-Allow-Origin: http://".$_SERVER['HTTP_HOST']);
        $augmentedUrl = $playbackbase."?authTicket=$authTicket";
        header("Location: $augmentedUrl");

Thank you.