Bluebird –
Would you mind adding a link to the site that you are trying to use the tabber on?
Make sure after you activate the plugin, you create a new tabber group. Once you have created the tabber group, go into the widgets page in the WP dashboard and fill each tabber (from the group you just created) with the widgets you want to appear in the tabber. Then, most importantly, add the tabber widget from the Available Widgets into the themes widget area that you want the tab to appear. Dont forget to select which tab group you want to appear in the widget options.
If you are still having problems, please let me know.
-matt