Well, I'm not positive yet, but it seems that removing the card, trying it in a different slot, then reinserting it made the difference. Its (for now) coexisting with the hard drive.
I am thoroughly confused by this A2000. It has 1M of chipram but says its revision is 4.3 (which is supposed to have only 512 according to the BBOAH). There are no signs of trace cutting or jumper soldering.
Also, is there a reason the 2091 only works in the closest zorro slot to the processor? Also, it seems that zorro slots have to be filled from the closest to the farthest without any gaps, otherwise they are not recognized. Is that standard, or is that an issue?