For the guy/gal that is mining on the P2Pool node cryptohasher.net, you've entered the wrong Darkcoin address:
Xm4sVvgCf7ENSyT4FJcLeo2oJpcwFaBAYwinvalid_address_0
They've got about 4.5mh so there's losing lots of coins the longer they keep the invalid address. I'm not sure how'd you contact the miner but all I gotta say is damn. Hope they see this post.
I've been putting a message up on the web-static interface on P2Pool when miners log in with incorrect details. WHat they've done there is put ADDRESS:0 or ADDRESS.0 thinking you need a worker name or password within the username field. Also I provide an IRC channel on my nodes, so I can talk issues out live with the miners themselves when they see the message.