app crash while testing with ios 5.0

I m trying to compile an app developped with ios sdk 4.3 with new ios 5.0 sdk

however, I get a strange crash at app loading with SIGABRT s开发者_如何学JAVAignal

the call stack is pretty minimalistic :

13 UIApplicationMain 14 main

after checking console, I get the following error:

Could not load NIB in bundle: 'NSBundle (loaded)' with name 'MainWindow_iPad''

I checked my resource folder , and the file is there, and the problem only occurs with the new xcode/ios sdk 5.0 , on a different machine with xcode 4 / ios 4.3 / ipad 4.3 with the same project, the project is not present

Does moving to ios 5 requires somes tweaks in resources management?

the beta version of xcode/ios 5 was bugged , with final version of ios 5 all is ok.