FB Share button is not being displayed anymore
===

I have a strange problem. The FB Share button has stopped displaying. The code used is

    <p style="margin-top:-50px; margin-left:300px; width:600px;">Join us on Facebook
    <a name="fb_share" type="button" share_url="http://xyz.com/"></a>
    <script src="http://static.ak.fbcdn.net/connect.php/js/FB.Share" type="text/javascript">
    </script>
    </p>

The code has not been changed since I was assigned to handle the website. Any ideas why this is happening? The HTML is there. But no button appears.

Thanks,
A.S.