From the sound of it, the SiS based Raid Controller isn't responding to the system. Is this on the same computer as the earlier question? From the looks of it, it might be a faulty raid controller or if the controller has Battery-backed write cache, it could be the memory going bad.
I'd attempt a driver update but to me this sounds like a raid controller failure. If its SiS, its probably a cheaper firmware-based one. If this system is mission critical it would be extremely wise to fork out the money for a full featured hardware based raid controller w/battery backed write cache. If anything, because they tend to have much better support and a very useful onboard tools for diagnosing these kinds of issues.
For more information on the differences, check out the Wikipedia article on RAID, it has info on the difference between full-featured hardware and firmware/driver based raid controllers.