Aeroplan doesn't have very many non-Star Alliance partners, and MU (China Eastern) and CZ (China Southern) are not one of them. Did you book this through a third party site like Expedia? That's the only reason I can think of why you could have entered an Aeroplan number, but you won't earn any miles for the flights.

You'll need to look at the partner pages of both airlines and see if you already have miles in one of those partner programs. If you're an infrequent flyer of Skyteam airlines then Delta Skymiles is probably best since they don't expire, although if a discount economy ticket you'll only earn partial miles for the CZ flights.