broken sword a shadow of templar the director cuts

I'm stuck at the part where Nicole found a note that had been encoded with a subtitution cipher...I've cracked the code but then I don't know what to do next...can't open the locked which has the picture of Lady Justice in the same room...can't leave the boathouse....what to do next???please helppppppppppppppppppppppppp...am i missing something?