WordPress Post Tabs not showing on page

I have had WordPress Post Tabs on my site for a very long time. Recently, it just stopped working. I am using the latest version and have changed nothing on that page since I installed it. Instead of the pretty tabs across the top of my page, I have a bulleted list. Nothing in the settings is helping and the “usage guide” for the plugin itself has no useful information.

Help? I just want it to work again.

http://lastshredsofsanity.com/skewed-design-studios/

http://wordpress.org/support/plugin/wordpress-post-tabs

http://wordpress.org/plugins/wordpress-post-tabs/