I just played a sewer scene and got to a guy that has a silver key but I couldn't pick it up because my inventory was full. I had picked up an extra parrifin canister. When I tried to go back to Abdul, Darien would not climb down the sewer ladder so I had to start over

(start over from my last save that is..not too bad really)
Still really liking this game. The baddies pop out and scare you half silly, lol.