Cedar Creek does use plywood, plus it is also tongue and groove, doubling the possibilities of squeaks. The best and easiest way is to pull back the carpet, "dust" the joints, then screw it down. Remember you'll be screwing into metal, so you'll need self-tapping screws. We had a problem with the floor squeaking between the bed and closet also, but it was a result of a flexing issue we had in the upper deck and pin box. That has all been repaired, now no more squeaks.
Hope this helps and God bless,