With his denunciation of pre-apartheid (i.e. pre-1948) white rule in South Africa, it seems highly unlikely that Tolkien's orcs and trolls serve, even unconsciously, as stand-ins for "Africans". A funny take on the "racism" debate: http://film.guardian.co.uk/lordoftherings/news/0%2C11016%2C863344%2C00.html best