hi Riffin,
are you on a XP deco tablet?
rotation technology is proprietary for wacom intuos 3/4/5/intuos pro tablets, and requires an art pen input stylus, purchased separately.
for every other tablet model, there's a choice between using tilt with some brushes, and having a locked rotation setting + adjustable custom angle degree slider for other brushes (oils, palette knives, maybe some other ones - I'm not sure.)