I picked this up recently, and I am on the second sequence doing Johnson's Errand and, when I get to the spot where you are supposed to shoot the barrels, either I do not have the gun with me or I cannot shoot. I tried reloading, but nothing happens. I tired pressing LT and then Y, but nothing happens. I tried pressing X, but what's his face just shakes the gun. Is that normal? Am I doing something wrong? Should I get a new copy? Help!