There's major issues going on with either the client and / or pool right now. You can read it in the chat, but I'm getting around 43% rejected shares on my main desktop. I have it set to restart every 15 minutes otherwise it starts reporting 100% rejects, stays at 100% cpu utilization and stops mining, or disconnects due to a getwork error.
Is there a linux miner compatible with pool mining?
Run it in Wine.