I had to wait years to see this film--it came out in 2004. Netflix is not always so quick to sort out distribution rights and such. The title alone magnifies the intrigue: what could make Darwin have nightmares? It could be a film about the rise of Creationism, for instance, or the vast spawning of evangelical anti-science conservatives.
Such a film wouldn't have to be about natural evolution at all. After all, 'survival of the fittest' and its application to the social and economic realm was not Darwin's idea; apparently he rejected such extrapolations.
This film is a slow and grim portrayal of the effects of a single-track economy in a country incapable of diversifying its revenue sources, or of creating jobs for a largely unskilled population. This could be any number of African countries, unfortunately, but Tanzania sets the scene for this particular portrayal.
In the end it was a disappointment. Why so many African economies fail to get off the ground deserves serious study, but using the Western liberal anti-globalization bias to frame a documentary does not adequately capture the problem. Instead it turns local poverty into a platform for liberal ideologies; anti-globalization in this case. Africans need jobs and better working conditions. Government regulation of extractive industries has failed, and 'survival of the fittest' rules. In that sense the film is correct, but western demand for African goods is not the true cause of Darwin's nightmare.