I wonder if it is being ddos'd in an effort to move/convert the 43K bitcoins that allegedly went missing from Instawallet? I'm trying to figure out if there is an advantage to be gained by having them offline for that or not.
If it was intentional a more informative error should have been used. I'm sure the ops team at mtgox is quite experienced but these basic errors pages seem like a big oversight once you are running a fairly high trafficked site.