those clips go straight to the wires so it seems unlikely that you have a short on the back of your box. i guess i would lossen the the bolts for the fuse panel and wiggle it around and see if you get rid of the ground. also, I'm not sure how the circuit is set up but getting a path to ground might be normal, the other end of the light bulb/whatever is attached to gorund.
I would unplug the switches/bulbs whatever you can and try it again. If it doesn't blow, start plugging things in until it does.