title: iPhone Simulator chrashes in NSKeyedUnarchiver after setting base SDK
body: <p>I started a project in xcode (3.2 on snow leopard) with base sdk 3.1.2. Now I changed this setting to 3.0 and it compiles without a warning. There are no problems running the app on the device, but the simulator crashes on launch every time with the following exception:</p>
  
  <blockquote>
    <p>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '[NSKeyedUnarchiver initForReadingWithData:]: incomprehensible archive (0x4e, 0x49, 0x42, 0x41, 0x72, 0x63, 0x68, 0x69)'</p>
  </blockquote>
  
  <p>I do not use the <code>NSKeyedUnarchiver</code>, so why is the app trying to call it? And what archive is incomprehensible? I reset the simulator before building, so there are no userDefaults or anything else around.<br>
  Thanks for your help!</p>