The following:
Installation - Fast Data Access MMU Miss error at the {ok} prompt
seems to imply a memory or other hardware fault although I have seen this and concluded it was caused by corrupted data either over the network (tftp boot stage).
Is your boot-device set to the correct hard disk device in the OBP?
What result do you get when you run probe-scsi-all from the OBP and is the disk you get listed the same device that the devalias for disk is set to?