Transition from multi layer to single layer

Question

I've got problem with my code. I make a transition from a single layer to a multi layer and then rotate the device. After that, i replace the multi layer back to a single layer, again. Everything works as expected until I rotate the device again, then...

Taaraaaa.. Application stop running.. Is there someone who can help me?? for code: SINGLE LAYER to MLUTI LAYER

- (void)goToGamePlayScene:(id)sender {
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"UIDeviceOrientationDidChangeNotification" object:nil];
[[CCDirector sharedDirector] replaceScene:[[[MultiLayerScene alloc] initWithGameBoardName:@"coba2"] autorelease]];

}

MULTI LAYER to SINGLE LAYER note:The following code is the code of the class being the son of a multi-layer class

[[CCDirector sharedDirector] replaceScene:[HomeScene node]];