I wonder if you're not exceeding the 8 Meg (16-bit, Zorro2) memory limit with your 8-Up, A2088, X-Serf, Deneb USB, etc. Everything in the Zorro2 slots must fit in that address space. I think Matthey is right, try it without the 8-Up card.
I think even SysInfo will show the address space each card tries to take. It should also show how much 16-bit Chip ram, 16-bit Fast ram and 32-bit Fast memory is installed.
