I don't think it ever mentions where the rain forest is. There are several, but in pop culture, "save the rain forest" always refers to the Amazon.
So, what have we here? A rain forest peopled by primitive natives. But no Amahuaca, no Huaorani, no Yanomami....In fact, they aren't Native South Americans of any kind. This supposed Amazon rain forest contains Caucasian elves. The female love interest is even lighter-skinned than the male white-guy hero (a reversal of the situation in Walt Disney's Pocahontas).
I get your point, but Asia and other continents have rainforests too. It might be too arrogant or whatever to claim most rainforests are associated with the Amazon so the movie is "wrong" if it doesn't include Indians. I already get criticized enough for being too picky and "PC" without taking on theoretical arguments like this one.
I think my point ties into something you might have said in your Rima post(s). FernGully is another example of someone placing an ancient enclave of whites in the middle of a territory that in reality is inhabited by indigenous tribes. Then the indigenous tribes take on the role of irrelevant savage interlopers. If they are even mentioned at all, and they aren't in FernGully, a tropical rain forest (central Africa, South America, or southeast Asia), inhabited only by Caucasian-looking fairies (some of them suntanned). I've not actually read the Tarzan books, but I wonder if Burroughs did this there, as well.
It's a valid point. Okay, here's a posting on it.
For more on the subject, see Stereotyping Indians by Omission and The Best Indian Movies.