Co-op not loading properly?

A friend (in Australia) and I (in the US) have been doing co-op LASO on Halo 2, and just recently in the middle of a level my game froze after taking a screen recording, and I, the host, crashed out to main menu. We tried starting up again 3-4 times and each time he would get kicked from the game while the level was “validating” (after the loading bar had filled). Anyone know what the cause of this might be? We each reset our consoles and still had the same problem.