That exemple is interesting. I happened to like Trollhunter a lot, amongst other reasons for its back-to-the-roots approach to trolls (even though there's a fair amount of modernist, positivist, rationalisation, such as UV lights playing the role of the sun at a "metabolic" level - but these are precisely compensated by the christian blood thing). I like Mike Mignola for similar reasons. I know very little about Norwegian culture, but I happen to be interested and reading a lot about european medieval folklore and its evolutions under church pressure, which does includes trolls and variations on all sorts of herr mannelig-like tales.
All comedies based on national stereotypes are problematic, as they reinforce prejudices (there's been interesting writings around "my big fat greek wedding", for instance). But even these have a limited impact, given that we kinda live in the same world, and have various tools to nuance it, including the awareness of the stereotypes to which we are reduced ourselves. The question is slightly different when it comes to exotic populations, or people from the other side of the Great Divide, our usual Others. Our common knowledge of traditionnal tribal cultures is limited and very much channelled through few sources, mostly documentaries and fictions. Think of the image of the amerindian in old western movies, or the way people envision amazonian tribes, "cannibals", etc. Such ways of life are remote enough (in access and in style) to make us dependant on a handful of storytellers. No surprise that they are, and always were, used as projection screens for our own fantasies, more than described for who they are. They ended up as receptacles for our dramatic images of fierce warriors, noble savages, pre-cultural aedenic innocence, animal-like pre-humans, etc. You can still see echoes of these in modern versions of colonial tales - the savages in Jackson's "King Kong", the indian in "The Brotherhood of Wolves" or the "Indian in the Cupboard", the natives of Disney's "Pocahontas", or even in science-fiction, with Avatar, STar Trek, Star Wars - which is less of an issue : while scifi still reproduces these convenient archetypes, they don't replace actual human identities with them.
But what Jamie Uys' film does is basically Mickey Mouse and the Boy Thursday. It's often our first and only contact with a population we know nothing about. The question is, what do we retain of it, what does it add to our vision of the world, geographically and philosophically. As a kid, I believed that this cute and heartwarming and "so pure" tribe was real, even if slightly caricatured like all the film's characters. It is presented so, an all-knowing voiceover describes the bushmen society and cultural values at the beginning of the film, if not all the long. There is no reason not to assume it's just establishing a "true" setting for a comedy. In a context where native rights are perpetually debated (how do you manage a modern society with more or less permeable pockets of strongly different cultures, how do you deal with special rights, non-forced assimilation, etc), the image that people have of natives societies have political impacts. Again, you can refer to the popular figure of the "indio" in south american countries, and the role it plays in state policies and political populism. Beyond that, there is whole visions of humanity that may be strengthened (evolutionism, biblical visions of morally pure origins, natives belonging to the realm of nature, rousseau-an corruptibility through society, etc), the very visions that romantic descriptions of natives were inspired by, and served to exemplify. It's a population's reality, hijacked to be replaced by our convenient fantasies.
So, there's a difference of degree. The distant myths that are built on such medias (fictions, or romantic spectacle-driven documentaries) are even more potent than prejudices amongst our neighbours. We're less armed against them, and they afford to be even more ignorant of realities : no film about XXth century norwegians makes them dress differently. Even though it's still caricatures of actual elements of former ways of life (some of these can be found in documentaries on the Africa of the 50s), it still takes more liberties than what we'd accept for more familiar settings. Ask yourself, after that film, what you "know" or "assume" about bushmen populations and way of life, even knowing that it is a comedy, even suppressing the most blatant comedic effects...
Anyway, you can argue that depicting even caricatured, outdated, fantazised cultural elements in an empathic way is better than depicting fierce savages like any old school colonial adventure would do. In that sense, the myth of the noble savage does encourage distanciation to our own cultural values, even if, to some extent, it takes reality in hostage for that. This is a better ground for further enquiry, than the symetrical way of demonizing "primitives". And I'm ready to bet that, amongst all the anthropologists who now loathe that film for the patronizing fantasy that it is, a huge lot of them had chosen that career out of curiosity and empathy generated precisely by that sort of romantic tale and depiction. Still, for many people who won't investigate further, the reality of natives is what is depicted in such films (and other glimpses will be rattached to it). People can't know what to "take" and to "leave".
It's no huge problem if people are aware of the bias of that film. Knowing it's a fiction doesn't suffice (you watch Hogan's Heroes, you still learn and retain there are wooden prisoner camps with watchtowers, barbed wires and germans in uniform), people can't evaluate which aspects are fictionous, exagerated, etc. They're a lot of components taken at face value. All it requires is a few notes contextualising it, the awareness of existing anthropological (and native) criticism. It's just that fans of that film just tend not to be aware of its questionnable aspects, and see it just as a nice comedy to the glory of some native population. It's got to be pointed that this film's universe is more largely a romanic fantasy than one would expect, and that it also does more disservice to the native's political reality than what the empathic fantasy of noble (puerile) savages would do at first sight. That's all.