That the file exists in your Xcode project folder isn't enough. Have you verified the file is properly referenced in your application target's build settings so it's properly copied into the app bundle? It's not quite the same as a standard resource (ie, it's not made a member of the target in the set of target membership check boxes) but rather a build setting because of its importance in a properly-formatted bundle.
Navigate to the project (select it in the Project navigator), select the application target in the list of targets, then click the Build Settings tab. Under the Packaging section, make sure the "Info.plist File" is properly set to the location/file name.
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