Ultimate Facebook Plugin not working

Hi,

I've installed the plugin, added my App ID and Secret from Facebook and have configured the other settings.

However, all that's appearing in my source code is:
<div class="wdfb_like_button"><fb:like href="http://smokefreediary.com/about/" send="true" layout="standard" width="300" show_faces="true" font=""></fb:like></div>

No Like button at all.

The code can be found on this page:
http://smokefreediary.com/about/