The problem with spiritual outlooks such as that espoused by the Secret (and Oprah) is the unspoken assertion that if a person finds themselves in dire straights, it is because they simply don't want to be happy and successful. The general idea is that whether we succeed or fail is almost entirely dependent on attitude and focus. By this logic, most of the citzens of Africa are lazy and uninspired, because of course famines, governmental corruption and lack of economic opportunity have nothing to do with it.
It's not surprising that the richest woman in the world would support such a concept. If one has riches then they are deserved, it argues, and likewise the poor suffer from a lack of motivation, and therefore get their just desserts. It's a perfect instrument for relieving guilt from the wealthy.
Also, I watched the trailer and it was the most idiotic thing I've ever seen, implying that "the secret" is some sort of mystical holy grail that has been jealously guarded by the elite for centuries, men have faught and died to protect it, if it ever got out it would change the world as we know it etc. It reminded me of the marketing campaign for the Segway. Yes, look how much the world has changed. Bored yuppies can ride a deformed scooter around town to show how leet they are. Give me a break.
They are just taking advantage of naive consumers who believe all they need to put their life in order is one more self-help book or movie. Generally speaking, the only people who truly profit from the self-help industry are the folks writing books and holding seminars. Baaaaaah Baaaaaaaaaaaaah. Poor sheeple