Uhm. You are missing the rotational temperature control stop. Not sure how that could cause a problem, but I have never installed a faucet without it. You can see the part in David's picture. See the large black part in the middle of this picture? That thingy tells your faucet when it has reached the max selected temperature. In your photo, below, you can see the teeth where it is supposed to mesh in but no black piece. My laptop is about three seconds from dead, so if you need me to clarify with some circles and such, I will have to do it late tomorrow when I get home.