Imagem, the Brazilian distributor of The River King, has the trailer of the film online. Go to "extras" and click on the speed of choice. You can also try the link via Blockbuster. Enjoy!
[edit: strangely, Imagem seems to have deleted the River King page. However, you should still be able to see the trailer through Blockbuster]
[edit #2: unembedded link here]