App crashes while using setContentViewController in iOS 5 - iphone

Question

I am making my app compatible to iOS 5 but the app crashes on the code where i have used setContentViewController.
Here is my code.
[[ChoicesViewController sharedChoices] setCurrentValue:[[(UIButton *)sender titleLabel] text]];
[self.choicesPopoverController setContentViewController:[ChoicesViewController sharedChoices]];
CGFloat popoverHeight = 44.0f * [[[ChoicesViewController sharedChoices] choices] count];
[self.choicesPopoverController setPopoverContentSize:CGSizeMake(380.0f, MIN(400.0f, popoverHeight))];
if ([self.choicesPopoverController isPopoverVisible]) {
[self.choicesPopoverController dismissPopoverAnimated:YES];
} else {
[self.choicesPopoverController presentPopoverFromRect:[(UIButton *)sender frame]
inView:self.view
permittedArrowDirections:UIPopoverArrowDirectionAny
animated:YES];
}
here is what shared choices returns:
static ChoicesViewController *_sharedChoices = nil;
+(id)sharedChoices
{
if (!_sharedChoices)
{
_sharedChoices = [[[self class] alloc] init];
}
return _sharedChoices;
}
//When i comment the below code , the app wont crash in iOS 5 but the UIPopover is not shown too. And if I uncomment it it will crash in iOS 5.
-(UIPopoverController *)choicesPopoverController
{
if (!choicesPopoverController)
{
choicesPopoverController = [[UIPopoverController alloc] initWithContentViewController:self];
}
return choicesPopoverController;
}

Answer 1

You say you set breakpoints and found this line was the problem :
[self.choicesPopoverController setContentViewController:[ChoicesViewController sharedChoices]];
but there's a few things going on there. Where does it crash if you change that line to
id controller = self.choicesPopoverController;
id shared = [ChoicesViewController sharedChoices];
[controller setContentViewController:shared];
?

Answer 2

Finally i found the solution :
instead of writing
[self.choicesPopoverController setContentViewController:[ChoicesViewController sharedChoices]];
i did
choicesPopoverController = [[UIPopoverController alloc] initWithContentViewController:[ChoicesViewController sharedChoices]];
and commented out the this code
/*
-(UIPopoverController *)choicesPopoverController
{
if (!choicesPopoverController)
{
choicesPopoverController = [[UIPopoverController alloc] initWithContentViewController:self];
}
return choicesPopoverController;
}
*/
Now it doesnt crash in iOS 5.