Hey guys, thanks for all of the replies.
@Mr. Seeker: I can push the filament by hand. I don't see any evidence of grinding. My adjustment screw is turned as far to the right as I can get it to go by hand.
@Daid: yup, gear is turning, pressure screw is maxed out, quick release is closed. Filament doesn't move.
@DDurant: I'll measure it this afternoon. I'm assuming that Netfabb doesn't have the lag problems of ReplicatorG?