After already having installed stock FRG01B, I tried installing the FRG22 from MDW using the stock recovery screen, and I get the E:Signature verification failed error. I've tried this with both the deodexed and non-deodexed versions and gotten the same error.
Any thoughts on how to proceed?
Purchased the Easy Root program off of the market, ran it, and it worked like a charm! Superuser access granted! I applied the FRG22 update (after everything got backed up) using ROM Manager, and things seem to be working just fine.