Dragon Age Origins: Lost in a Dream Quest?

I seem to be stuck because I have the mouse, fireman, and spirit form but I can’t seem to get the Golem form; I think I might have killed the mage in “the room upstairs” because I have no more enemies to fight except the ones in the mive doors which I can’t open. Help Please. How do i become the shapeshift Golem in Dragon Age Origins, Lost Dream Quest?