Rainman, you're supposed to be riding the bike up those hills, not walking.
I guess checking cleats for excessive wear before each ride can be added to the checklist; along with brakes, tire pressure, quick releases, etc.
Thanks for the info. I guess I'll re-lube my cleat screws every so often to prevent the problem you are having.
I hope you don't destroy the shoe in the process of removing the screw.