xcode b6 问题

func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {
    var mainTabBar = HBTabBarController()
    self.window?.rootViewController = mainTabBar
    self.window?.makeKeyAndVisible()
    return true
}
2014-08-23 12:05:46.281 swiftTest[1939:80920] Unknown class _TtC9swiftTest14ViewController in Interface Builder file. 2014-08-23 12:05:46.300 swiftTest[1939:80920] 17545849:_UIScreenEdgePanRecognizerEdgeSettings.edgeRegionSize=13.000000 2014-08-23 12:05:46.329 swiftTest[1939:80920] 17545849:_UIScreenEdgePanRecognizerEdgeSettings.edgeRegionSize=13.000000 2014-08-23 12:05:46.333 swiftTest[1939:80920] 17545849:_UIScreenEdgePanRecognizerEdgeSettings.edgeRegionSize=13.000000 2014-08-23 12:05:46.336 swiftTest[1939:80920] 17545849:_UIScreenEdgePanRecognizerEdgeSettings.edgeRegionSize=13.000000

请问以上在xcode6 b6 是什么问题啊