title: presentViewController doesn't work in ios 6
body: <p>I used the following code to switch to another xib:</p>
  
  <p>-(IBAction)switchpage:(id)sender
  { </p>
  
  <p>JazzViewController *jazz = [[JazzViewController alloc] initWithNibName:"JazzWindow" bundle:nil];</p>
  
  <p>jazz.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
  [self presentModelViewController:jazz animated:YES];</p>
  
  <p>}</p>
  
  <p>changed it to this code for iOS 6:</p>
  
  <p>-(IBAction)switchpage:(id)sender
  { </p>
  
  <p>JazzViewController *jazz = [[JazzViewController alloc] initWithNibName:"JazzWindow" bundle:nil];</p>
  
  <p>jazz.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
  [self presentViewController:jazz animated:YES completion:nil];</p>
  
  <p>}</p>
  
  <p>But it still doesn't work in IOS 6 (crashes back to Xcode with signal SIGBRT), 
  it does work in iOS 5  en 5.1 at my simulator.
  Anyone an idea of what I should do??</p>