I had the exact same issue with a MBP 17" unibody this evening. Precisely the same error code. I booted from my Snow Leopard DVD and ran a disk verify. It indicated there were problems and that I ought to repair the disk. Attempted the repair and it failed. The wizard suggested that I "back up as much of my data as possible" and essentially wipe the drive and start over. Fortunately, I had a timemachine backup made this afternoon. I'm currently formatting my drive. There had been no significant recent changes that I can think of to cause such a problem. Most recent installation of any software was Office 2011 around a week ago, but I've been using all sorts of other programs since then. :/ Such is the world of technology, eh?