Don't know. There's a thread from the other day started by withnail69 with the same problem, among others.
http://www.blackberryforums.com/gene...ml#post1676492
Apparently his issue with the lock button anyway was an OS bug... or at least he reports it went away when he downgraded the OS.
If there's any change of moisture exposure, you should remove the battery now and go read the FAQ article on what to do if you get your blackberry wet.