Could not load NIB in bundle [...] with name 'MainWindow' only on iPhone 4

I have a Problem with my App. It is working perfectly on my iPhone 3GS, but now where I tried to test it on an iPhone 4, it is crashing while the Splashscreen is visible.

Here's the log:

2011-07-06 16:01:05.611 Apptest [294:607] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Could not load NIB in bundle: 'NSBundle </var/mobile/Applications/0C371068-7E74-4C54-997C-80E3B0929411/Apptest.app> (loaded)' with name 'MainWindow''
*** Call stack at first throw:
(
    0   CoreFoundation                      0x311ec64f __exceptionPreprocess + 114
    1   libobjc.A.dylib                     0x3494dc5d objc_exception_throw + 24
    2   CoreFoundation                      0x311e开发者_高级运维c491 +[NSException raise:format:arguments:] + 68
    3   CoreFoundation                      0x311ec4cb +[NSException raise:format:] + 34
    4   UIKit                               0x368c9a53 -[UINib instantiateWithOwner:options:] + 1110
    5   UIKit                               0x368cae09 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 92
    6   UIKit                               0x366f54cd -[UIApplication _loadMainNibFile] + 96
    7   UIKit                               0x366efb09 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 180
    8   UIKit                               0x366c47d7 -[UIApplication handleEvent:withNewEvent:] + 1114
    9   UIKit                               0x366c4215 -[UIApplication sendEvent:] + 44
    10  UIKit                               0x366c3c53 _UIApplicationHandleEvent + 5090
    11  GraphicsServices                    0x36398e77 PurpleEventCallback + 666
    12  CoreFoundation                      0x311c3a97 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 26
    13  CoreFoundation                      0x311c583f __CFRunLoopDoSource1 + 166
    14  CoreFoundation                      0x311c660d __CFRunLoopRun + 520
    15  CoreFoundation                      0x31156ec3 CFRunLoopRunSpecific + 230
    16  CoreFoundation                      0x31156dcb CFRunLoopRunInMode + 58
    17  UIKit                               0x366eed49 -[UIApplication _run] + 372
    18  UIKit                               0x366ec807 UIApplicationMain + 670
    19  Apptest                             0x00002a0b main + 82
    20  Apptest                             0x000029b4 start + 40
)
terminate called after throwing an instance of 'NSException'

I hope you can help me. Thanks in advance.

Does the MainWindow.xib actually exist in your project?

You may have deleted it by accident. It may still work on the 3GS even if you deleted it from your project as it may well still be in the bundle on the 3GS.

I normally clean my projects and reset the simulator/uninstall the app from my device if I get inconsistencies like this.