I had the same problem.... I took it all apart lubricated everything, checked everything. Same result.
So.... I changed the batteries. Fresh batteries work perfectly! I initially used rechargeables that clearly didn't have enough juice.

The deadbolt may very free inside the deadbolt hole... This system is low torque and a over torque clutch may slip if the dead bolt it's not completely free inside the deadbolt hole... Also, if you try to open the door before to unlock it, you may block the deadbolt... take care to unlock the door before open it. to be sure that the dead lock is ok, you can turn the manual knob and be sure is turning very very easily.

Also are you no that POWERBOLT is a 3 codes memory? go to that link to see more info about that : http://www.fixya.com/support/t8006865-not_overwrite_old_codes_just_keeps

Have a good lock
Have a good unlock