I don't see how Cream had any influence on Zeppelin, They were basically contemporaries, Cream might have done certain things first, but in my opinion they did them poorly. Cream was not that great of a band, they were pretty lame and boring, and Eric Clapton is one of the most boring musicians of all time. These are of course just my opinions and therefore will probably be unpopular but I must say that I'm not impressed at all with Cream.