I'm the writer of the www.NoShockZone.org blog on electrical safety as well as the moderator of the AC Power & Grounding Forum on ProSoundWeb.com magazine, so I'm very interested in what's going on with your grounding problem. At first blush this appears to be an open neutral feeding your house, but not all the pieces fit. Please email your phone number to mike@noshockzone.org so we can discuss this a bit.