Just returned from REI trying to exchange these poles. Had problems with locking.
REI doesn't carry the original poles I bought, I guess comperdell redisigned them. I ended up not exchanging since the new ones seem to be longer, and have different handles (the hold that sticks out is smaller, and there is some extra plastic on top of handles). I ended up not exchanging them since after some tweaking I ended making my old poles work.
REI suggested that i only open the locking mechanism just enough to allow the poles to slide, not all the way out. that seems to help to get the grip on the locking mechanism.