SIGABRT error during interface change

(IBAction)switchAppointment {

    AppointmentController *appt = [[AppointmentController alloc] initWithNibName:nil bundle:nil];

    appt.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;

    [self presentModalViewController:appt animated:YES];

    [appt release];
} 

That is the code that I use to switch from one .xib 开发者_如何学Pythonto another, however on the line that says "self presentModalViewController:appt animated:YES" , I'm getting a SIGABRT error. My app crashes immediately when I try to go into that interface.

FYI too I'm on Xcode 4.2, but it was doing this before I downloaded the beta.

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I have also same answer for the code:

 nextView *second=[[nextView alloc] initWithNibName:nil bundle:nil];
[self presentModalViewController:second animated:YES];      
[second release];

Yours

Miska