[Ruy Dias de Bivar]

I figure it was probably in South America because of the blow darts.

[greene66]

Maybe something like “Secret of the Incas” (1954)? Just a guess, as it used to circulate a bit on the late-shows. But I don’t recall the scene you’re describing.

[libertarian27]

I think FijiHill got it - ‘East of Sumatra’
http://www.imdb.com/title/tt0045716/