I'm stuck in Dark Messiah! I need help!!  

Hello, I'm playing this fantastic game, Dark Messiah. But now I'm stuck in a place! I'm in the beginning of the game, I am arrived at a sort of old temple (it seems a Tomb Raider level), I traveled with a ship with a girl. There is a girl outside who is coming with me and I must find a way to open a broke lock! There is a portal but when I try to open that portal, lever will fall down! ^__^. I can't use this lever anymore...but I can't find other way to get in! My objective is to open portal and let girl to come in and go togheter in the temple. I hope you understood....how to go on?