You mean open up the Arcanum module? I can't remember now. Think you may have to undat it all and stick it in an Arcanum\Modules\Arcanum_Undatted directory. At least I think that's what I did when I was mucking around with it a while back.
damn, when i tried to edit arcnum i spendt 3 hour before i figured it ou, i should've just asked here...