title: Parsing JSON using AFNetworking 2.0 exception
body: <p>i have an issue handling the JSON parsed data using AFNetworking.</p>
  
  <p>here's my code:</p>
  
  <pre><code>        AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
          manager.responseSerializer = [AFHTTPResponseSerializer serializer];
          NSDictionary *parameters = @{@"strEmail": _logInEmail.text, @"strPassword":_logInPassword.text};
          [manager POST:@"http://carefid.com/api/user/login.php" parameters:parameters success:^
  
            (AFHTTPRequestOperation *operation, id responseObject) {
  
  
  //NSString *string = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
                NSString *str = responseObject[@"error"];
              NSLog(@"JSON: %@", str);
              UIViewController *myController = [self.storyboard instantiateViewControllerWithIdentifier:@"rootController"];
              [self presentViewController:myController animated:YES completion:nil];
  
          } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
              NSLog(@"Error: %@", error);
          }];
  </code></pre>
  
  <p>when im trying to log the value i get this error:</p>
  
  <pre><code>2014-07-15 14:39:08.438 carefid[7858:60b] -[_NSInlineData objectForKeyedSubscript:]: unrecognized selector sent to instance 0x1094c67a0
  2014-07-15 14:39:08.441 carefid[7858:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[_NSInlineData objectForKeyedSubscript:]: unrecognized selector sent to instance 0x1094c67a0'
  *** First throw call stack:
  (
      0   CoreFoundation                      0x0000000101d48495 __exceptionPreprocess + 165
      1   libobjc.A.dylib                     0x00000001019c399e objc_exception_throw + 43
      2   CoreFoundation                      0x0000000101dd965d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
      3   CoreFoundation                      0x0000000101d39d8d ___forwarding___ + 973
      4   CoreFoundation                      0x0000000101d39938 _CF_forwarding_prep_0 + 120
      5   carefid                             0x000000010001f14f __34-[ViewController existingUserBtn:]_block_invoke + 95
      6   carefid                             0x0000000100015648 __64-[AFHTTPRequestOperation setCompletionBlockWithSuccess:failure:]_block_invoke46 + 40
      7   libdispatch.dylib                   0x0000000102669851 _dispatch_call_block_and_release + 12
      8   libdispatch.dylib                   0x000000010267c72d _dispatch_client_callout + 8
      9   libdispatch.dylib                   0x000000010266c3fc _dispatch_main_queue_callback_4CF + 354
      10  CoreFoundation                      0x0000000101da6289 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
      11  CoreFoundation                      0x0000000101cf3854 __CFRunLoopRun + 1764
      12  CoreFoundation                      0x0000000101cf2d83 CFRunLoopRunSpecific + 467
      13  GraphicsServices                    0x00000001040bef04 GSEventRunModal + 161
      14  UIKit                               0x0000000100570e33 UIApplicationMain + 1010
      15  carefid                             0x0000000100049183 main + 115
      16  libdyld.dylib                       0x00000001028cd5fd start + 1
  )
  libc++abi.dylib: terminating with uncaught exception of type NSException
  </code></pre>
  
  <p>What could cause this problem? is the responseObject is an dictionary?
  if my code is wrong, how should I handle this?</p>