The message is in hex (which is probably a mistake). It's hdc2 and hdc1.
> I've tryed to e2fsck /dev/hdc2 (thinking that device 16:02 corresponds
> to /dev/hdc2) and it found a lot of errors, but it seemed that e2fsck
> was able to correct them all; after rebooting similar messages appeared
> again after some hours.
> Any clue about this?
Any random core dumps? This is going to sound stupid, but check for bad RAM.
Any bad block (I/O error) messages?