Well we're at the point there where a number of things could lead to a World War, so I don't see why there couldn't be a path that way if China is broken up.
I was actually just wondering about the possible mechanics of the western powers dividing China into colonies and what it would take to happen. I think there's a big problem getting China broken up by the time of the Boxers, though. It would put so much stress on the power relations between the European powers that support for it might be impossible, especially considering they had just beaten China and controlled the center of government and extracted concessions of huge amounts of silver. They already demonstrated a massive amount of influence. Why spend even more resources splitting China up?
ED: Also, notably China was huge and populous even then. COULD the Western Powers have split it up at all effectively?