I assume you have a Zorro2 harddrive-controller. If it is a dma capable one, like for example the A2091 or GVP HC+8, you need to make sure the Mask for all partitions and in all mount-lists for CD-ROMs etc are set to 0xFFFFFF, or else it will freak out if you enable memory it cant reach - Zorro2 cards cant reach memory located above the first 16MB and this Mask value prevents them from even trying.
/Patrik
