The NuBUS Jackhammer doesn't auto-terminate like the PCI version. There are three spots for 3 terminator resistor packs (they're blue in color.) You have to take them out or put them in depending on the configuration you want for your card.

See here: http://picasaweb.google.com/lh/photo/aFy3q1qWvobqicTFhlp5Ng

3 blue resistors on the left side of the card. You may already have them.