How to get StumbleUpon pages to work for one URL from many different locations

Question

I have a little part of my page devoted to liking the page itself:

Now, all of the social buttons work, except that the StumbleUpon button generates an error.

This is the code I used for the button:

<!-- Place this tag where you want the su badge to render -->
<su:badge layout="2" location="http://www.yannbane.com"></su:badge>

<!-- Place this snippet wherever appropriate -->
<script type="text/javascript">
  (function() {
    var li = document.createElement('script'); li.type = 'text/javascript'; li.async = true;
    li.src = ('https:' == document.location.protocol ? 'https:' : 'http:') + '//platform.stumbleupon.com/1/widgets.js';
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(li, s);
  })();
</script>

The error's I'm referring to:

Unable to post message to http://www.stumbleupon.com. Recipient has origin http://www.yannbane.com.

I have two questions:

1. Will this affect my page's performance on SU?
2. If so, how can I fix it?