I had one similar on a true s8800. Gave the same message but I'm not 100% sure how I cleared it. I booted the server with a monitor and went into the RAID utility. I thought I messed it up worse since after I was done, the 2 drives refused to be added to a logical array when they were in an array when I started. I restarted the server and CM was then able to format, partition, and install. Not sure if that helps. It was a CM5.2 btw but the same exact screen/error.
-CL