In CCPackageManager.m at method "savePackagesForceWriteToDefaults:(BOOL)forceWrite" the app crashes at the line containing: [userDefaults setObject:packagesToSave forKey:PACKAGE_STORAGE_USERDEFAULTS_KEY];
I had to hack the method to stop the crashes occurring. Let me know and I'll add crash logs from before the hack (or restore the commented code).
Please note that the highscores are saved in userDefaults just fine. But this code executes on entering background.