Same thing here.. I was searching the error in Google and found a bunch of blog/forum posts saying that adding the following comment line to /etc/hosts, restarting iTunes, and trying it works:

# 74.208.10.249 gs.apple.com

I was totally skeptical because it's a comment line, but I thought, "wtf, i'll give it a shot. it's just the hosts file." and it worked.

iPhone is restoring now with 9a5274d.

Try updating OTA, it worked perfectly for me.

Perhaps you have TinyUmbrella installed?