Robert Schuller has preached that the Gospel is about self-esteem for the last thirty years. He has consistently stated that a preacher should not preach about sin. Rather, preachers should remind people of their great possibility as human beings. He has espoused the "Gospel of Positive Thinking."
Robert Schuller has been and is a false shepherd who preaches a false gospel. There is an interesting story that Al Mohler has addressed in his blog concerning the Schuller family. Take a look at the story here.