xcode错误：程序接收信号SIGABRT，非常简单的程序tho

Question

我正在尝试编写一个计算我朋友吃的翅膀数量的程序，同时计算已经过去的时间量。相当简单，我制作的程序没有错误编译，但是当我去运行它时它给了我一个错误。这是相关的错误（我认为）：

  

2011-11-16 15：41：31.157 WingChallenge [5530：f803] * 由于未捕获的异常'NSUnknownKeyException'而终止应用程序，原因：'[setValue：forUndefinedKey：]：此类是关键时刻不符合关键值编码。'

以下是相关代码：

- (IBAction)wingPlus:(id)sender {

    wings +=1;
     NSString *wingsTemp = [[NSString alloc] initWithFormat:@" %i !", wings];
    self.wingsEaten.text = wingsTemp;

}
- (IBAction)clear:(id)sender {

    wings = 0;
    NSString *wingsClear = [[NSString alloc] initWithFormat:@"Back to zero!"];
    self.wingsEaten.text=wingsClear;
}

-(void)countup {
   seconds +=1;
   if (seconds >= 60) {
       seconds=0;
        minutescount +=1;

 }
    minutes.text=[[NSString alloc] initWithFormat:@"%i", minutescount];
    secondslabel.text=[[NSString alloc] initWithFormat:@"%i", seconds];
}


- (IBAction)startTimer:(id)sender {

   seconds=0;

    [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(countup) userInfo:nil repeats:YES];
}

来自头文件：

- (IBAction)wingPlus:(id)sender;
@property (weak, nonatomic) IBOutlet UILabel *wingsEaten;
- (IBAction)clear:(id)sender;
@property (weak, nonatomic) IBOutlet UILabel *minutes;
@property (weak, nonatomic) IBOutlet UILabel *secondslabel;
- (IBAction)startTimer:(id)sender;