title: sigabrt on filteredArrayUsingPredicate
body: <p>I'm a noob and trying to convert an example from a book into an app I can use.  </p>
  
  <p>The sample app is a modified version of the contacts application and it works.</p>
  
  <p>I've done some further modification, and the search no longer works.  It sigabrts on the following line</p>
  
  <pre><code>self.filteredAnswercards = [flattenedArray
                              filteredArrayUsingPredicate:predicate];
  </code></pre>
  
  <p>I'm stumped.
  my head is bloody from beating it against my keyboard.   </p>
  
  <p>ANY help is massively appreciated.</p>
  
  <p>Thanks.</p>