I just played Ultima IV about a month ago. I tried playing it on my expanded A2000 68060, Kickstart 3.1, ECS Denise, and 2MB chipram. But I couldn't get it to work even with the 68060 disabled and the fastram disabled. After loading from the floppy it would just freeze.
I finally got it to work on my A500 with Kickstart 1.3, 512KB chipram, OCS Denise, and no fastram. With fastram installed I would get graphic corruption and sound problems.
This game seems to be very picky. I don't think that it likes your extra chipram or your ECS Denise.