title: XCode error: "GDB:Program received signal: "SIGABRT"."
body: <p>I am writing a simple application using cocos2d 0.99.5, the iPhone SDK is 4.2. I have run my application on device, but when I press the button to switch CCScenes, sometimes the app suddenly has no response and XCode received the error:"GDB:Program received signal:"SIGABRT". " </p>
  
  <p>This issue happens by accident. You have to press the transition button many times to reproduce this bug.</p>
  
  <p>I have learned that SIGABRT is raised by the abort() function. abort() is called by the standard assert() macro when an assertion fails. But there is no assert function in my program.</p>
  
  <p>Could anyone tell me how does this problem happen, and how to solve this problem?  I don't know what to do next now. </p>