I have a ton of experience with my A2091 and my PP&I 2000/040 board. 040 boards and the A2091 have notorious problems, until you get all the chips updated. Once you get all the chips updated and the patches installed, things will run smoothly.
I had the same problems. I think I had to upgrade to the 7.0 ROMs and also upgrade the Western Digital chip on the board to the -08 version (the latter chip wasn't that expensive, as I recall).
Later on, I bought the GURU-ROM for this board, which also works well (this is not necessary if you have the 7.0 ROMs, but it doesn't hurt).
Make sure you have the proper version of the WD chip though - that would be the first thing I would try. Also make sure there is some RAM installed on the A2091.
Also, check the board....are the terminating resisitors by the internal SCSI slot present or removed? If removed, then you will have to terminate the external connector with a DB29 type external terminator.
You will also notice that things are transferring very slowly on the SCSI bus. There is a DMA problem when using an 040 and the A2091 in conjuction. I used the patch available on Aminet called vbak2091 (or something similar) to increase the SCSI speed back to normal levels. This seems to be the best of all the patches I tried.
