This problem came to me in Xcode 4.2 because I had added one property on the button and then that property is synthesized. As I remove that property and synthesize paraphrase. my program stop working. I thought to create a new project and try again. I did that twice but got the same error. Then when I developed a calculator and searched over the net but did not get the problem solved.
Then after a long search, I came to know that button’s delegate was still assigned.
So I went to “Show the connections inspector” in the right corner and removed the delegate…and my program started working..!!
Hope this would help you guys…..