Are you trying to display this template for mashups or for single posts?
If it’s for mashups, you will need to get the postid from the poi rather than relying on the global $post variable:
$post = get_post($poi->postid);
…your code here…
You might also want to try just placing that code in your theme to verify that it’s working before trying to use it in the map poi…
If that doesn’t help, please send me the template so I can take a look (you can just paste it into the contact form on the site).