i've got the error after cloning a machine from an esx2.5.2 to an esx3 update1 one.
the machine starting up. trying to load windows 2000. and suddently shutting down.
we've found the problem...
there's was a driver in the vm, it worked when we remived it.
we think it happend cause the driver is like creating another device in the vm... and we all know the vm is limited with devices.
anyway, a removal of an ATA driver of a HD fixed the problem. we cloned the vm again, and it worked fine.