I replaced two old GFCIs today (changing from beige to white) and something went wrong. One of them works fine, but the other didn't. I figured I must have got the load/line switched, so I swapped them, and then the house circuit breaker tripped. I replaced the new GFCI with another new one, and the circuit breaker tripped again. I replaced the GFCI with a regular outlet. Same thing happened. I tied the wires together (temporarily, just to see what would happen) and the breaker tripped. I am just SO frustrated right now.

I just have no idea what it could be. Any ideas?