I know a subpanel in a separate location must be grounded locally, but does it also have to be grounded to the panel? Isn't there some prohibition against grounding in two places?
You need to realize that ground rods, and equipment grounding, are two VERY DIFFERENT THINGS.
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.