same here.. my payout address was changed as well to 5mdNFTqXfQivAZDoccL9S1VPvHxTjk1fw6 (dont know whose that is) and i lost about 16k coins..
I dont think its the password or pin.. i think someone got in during the ddos attacks and changed the payout address..
*edit* if anyone is feeling generous.. pls donate to : 5VSccduxxNaRv7Xmx8wn5Zx4nchURin86C. The 16k coins gone was pretty much 14 hours of my entire hashing power.. Crap this sucks..