title: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSURL initFileURLWithPath:]: nil string parameter'
body: <p>I am trying to play back 4 audio files at random when they are called. here is code</p>
  
  <pre><code>  // randomize the playback on the setShot files
     int randomNumber = arc4random() % 4 + 1;
     NSString *tmpFileName = [[NSString alloc] initWithFormat:@"SetShot%d", randomNumber];
     NSString *fileName = [[NSBundle mainBundle] pathForResource:tmpFileName ofType:@"aif"];
     SystemSoundID soundID;
     AudioServicesCreateSystemSoundID((__bridge CFURLRef)[NSURL fileURLWithPath:fileName], &amp;soundID);
     AudioServicesPlaySystemSound (soundID);
  </code></pre>
  
  <p>I am getting the above crash on my device not in the simulator. I am fairly new to coding.
  Thanks for all your help.</p>
  
  <p>The sound files are SetShot01 thru to SetShot04</p>
  
  <p>ARC-armv6,armv7 xcode 4.3.2 on device with 5.1.1</p>