I need help with Ghostbusters: The Video Game on PS3?!?

In the last level at Central Park Cemetery, I've come to an obstacle where there is a small gate attached to a weight that is held up by a huge pile of skulls. I stood there for an hour blasting that pile of skulls with every weapon available and it has no effect at all. I also tried moving the weight around with the Slime Tether. (The Capture Stream wouldn't grab it.) I sat there trying to destroy it for over an hour and I got so frustrated that I started the game over from the beginning. I think I might have overlooked something or not done something that I was supposed to do before, as Ray stands in a different section of the cemetery and keeps telling me to come back to where he is.