Thank's for your answer.
Difficult, I don't think so; at shutdown the system unmount all partitions and after a "normal" shutdown I've got the error after the boot with grub.Hrm, I think that error occurs when you try to run a non-unmounted ext3 (and ext2?) partition, could that be the case?
hda8 is a logical partition... is maybe the problem (should i use a primary partition?)?