UIActivityIndicatorView 부분을 코딩하고 문제가 발생하였습니다.

최강사님. 안녕하세요. 강사님 강의를 듣다가 문제가 생겨서 이렇게 질문을 드립니다. 상황은 제목과 같이 UIActivityIndicatorView 부분을 코딩하고 실행을 했을 때 콘솔부분에 아래와 같은 내용이 나오며 실행되지 않고 있습니다. 2016-07-01 16:23:05.353 MiniBrowser[20606:3090578] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key spiningActivityIndicator.' *** First throw call stack: ( 0 CoreFoundation 0x0000000101cccd85 __exceptionPreprocess + 165 1 libobjc.A.dylib 0x0000000103a70deb objc_exception_throw + 48 2 CoreFoundation 0x0000000101ccc9c9 -[NSException raise] + 9 3 Foundation 0x000000010209e19b -[NSObject(NSKeyValueCoding) setValue:forKey:] + 288 4 UIKit 0x0000000102687d0c -[UIViewController setValue:forKey:] + 88 5 UIKit 0x00000001028be7fb -[UIRuntimeOutletConnection connect] + 109 6 CoreFoundation 0x0000000101c06890 -[NSArray makeObjectsPerformSelector:] + 224 7 UIKit 0x00000001028bd1de -[UINib instantiateWithOwner:options:] + 1864 8 UIKit 0x000000010268e8d6 -[UIViewController _loadViewFromNibNamed:bundle:] + 381 9 UIKit 0x000000010268f202 -[UIViewController loadView] + 178 10 UIKit 0x000000010268f560 -[UIViewController loadViewIfRequired] + 138 11 UIKit 0x000000010268fcd3 -[UIViewController view] + 27 12 UIKit 0x0000000102565fb4 -[UIWindow addRootViewControllerViewIfPossible] + 61 13 UIKit 0x000000010256669d -[UIWindow _setHidden:forced:] + 282 14 UIKit 0x0000000102578180 -[UIWindow makeKeyAndVisible] + 42 15 UIKit 0x00000001024eced9 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 4131 16 UIKit 0x00000001024f3568 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1769 17 UIKit 0x00000001024f0714 -[UIApplication workspaceDidEndTransaction:] + 188 18 FrontBoardServices 0x00000001059018c8 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 24 19 FrontBoardServices 0x0000000105901741 -[FBSSerialQueue _performNext] + 178 20 FrontBoardServices 0x0000000105901aca -[FBSSerialQueue _performNextFromRunLoopSource] + 45 21 CoreFoundation 0x0000000101bf2301 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17 22 CoreFoundation 0x0000000101be822c __CFRunLoopDoSources0 + 556 23 CoreFoundation 0x0000000101be76e3 __CFRunLoopRun + 867 24 CoreFoundation 0x0000000101be70f8 CFRunLoopRunSpecific + 488 25 UIKit 0x00000001024eff21 -[UIApplication _run] + 402 26 UIKit 0x00000001024f4f09 UIApplicationMain + 171 27 MiniBrowser 0x0000000101ae4f62 main + 114 28 libdyld.dylib 0x000000010453492d start + 1 29 ??? 0x0000000000000001 0x0 + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException 또한 appDelegate.swift 부분이 나오며 class AppDelegate: UIResponder, UIApplicationDelegate { 이부분이 음영처리 되면서 오른쪽에 "Thread 1: signal SIGABRT" 라고 나오고 있습니다. 혹시나 하여 강사님께서 올려주신 자료를 복사하여 해봐도 똑같은 현상이 나타나고 있습니다. 어떤 것을 잘못한 것인지 판단되지 않아 질문을 올립니다. 그럼 답변기다리겠습니다. 감사합니다.