[Plugin: Tabber Tabs Widget] Theme Integration

I love the Tabber Tabs Widget and it works great for me when installing it in the standard way (to the wp-content/plugins/ folder).

My question is about integrating the plugin into a theme. I have it half way working. It’s generating the sidebar area but not the actual widget.

Basically, I’ve just updated the constant back path to where the plugin is located in my theme files:

define( 'TABBER_TABS_DIR', TEMPLATEPATH . '/includes/plugins/tabber-tabs-widget/' );

But it’s not loading the widget for some reason. Any idea what I might be missing?