Strange UIKit crash

Question

Hi people, my app sometimes crashes when I try to open new view controller, it's looks like if uikit could't load nib file, but in most cases this controller loads fine. I can't determine cause of this problem.

Thread 0 Crashed:
0   libSystem.B.dylib               0x00090b2c __kill + 8
1   libSystem.B.dylib               0x00090b1a kill + 4
2   libSystem.B.dylib               0x00090b0e raise + 10
3   libSystem.B.dylib               0x000a7e34 abort + 36
4   libstdc++.6.dylib               0x00066390 __gnu_cxx::__verbose_terminate_handler() + 588
5   libobjc.A.dylib                 0x00008898 _objc_terminate + 160
6   libstdc++.6.dylib               0x00063a84 __cxxabiv1::__terminate(void (*)()) + 76
7   libstdc++.6.dylib               0x00063afc std::terminate() + 16
8   libstdc++.6.dylib               0x00063c24 __cxa_throw + 100
9   libobjc.A.dylib                 0x00006e54 objc_exception_throw + 104
10  CoreFoundation                  0x00026b2c +[NSException raise:format:arguments:] + 76
11  CoreFoundation                  0x00026acc +[NSException raise:format:] + 24
12  UIKit                           0x000893f8 -[UIViewController _loadViewFromNibNamed:bundle:] + 292
13  UIKit                           0x000890b8 -[UIViewController loadView] + 120
14  UIKit                           0x00069750 -[UIViewController view] + 44
15  UIKit                           0x00088fd8 -[UIViewController contentScrollView] + 24
16  UIKit                           0x00088d90 -[UINavigationController _computeAndApplyScrollContentInsetDeltaForViewController:] + 36
17  UIKit                           0x00088c3c -[UINavigationController _layoutViewController:] + 28
18  UIKit                           0x0008863c -[UINavigationController _startTransition:fromViewController:toViewController:] + 504
19  UIKit                           0x000883a8 -[UINavigationController _startDeferredTransitionIfNeeded] + 256
20  UIKit                           0x0007049c -[UINavigationController pushViewController:transition:forceImmediate:] + 776
21  UIKit                           0x00070180 -[UINavigationController pushViewController:animated:] + 36

This is code:

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:@"PlaylistEditViewController" bundle:nil]) {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(selectSongs:) name:@"selectSongs" object:nil];
    }
    return self;
}