hold on a sec, ill find it for you.
EDIT: okay, is this after chapter 2 or after chapter 3?
EDIT2: okay, you must mean chapter 2. tell me, are you in b1? and you've gone as far right as you can, and you're stuck at a wall, right? well turning to slim in 3-D should let you slip through a crevice in the wall. if you're still lost, take a pic of where you are.