who ever was responsible for the listing doesn't like him any more than I do. HA! He doesn't come up until you hit the "full cast and crew" button and then there he is at the end.
The credits at the beginning of the movie lists all the actors and then says "and introducing Horst Buchholz". The folks at Imdb probably just copied this and that is why he is the last on the list. That's my guess.