Did you have installed properly and enabled the add-on in your add-on menu? Do you have other tabs from other add-ons; i.e. JVS? (1)
Yeah, I'm not sure how to fix that without changing the duplicator itself. (2)
(1) yes i have wedges, dirt, jvs, (basically multiple tabs)
(2) aww that stinks
edit: i have only 4 cube add ons installed, large cubes, fraction cubes, 2x2 cubes, 6x cubes. i hope this helps