title: Why an NSException error?
body: <p>I have put the following code in...;</p>
  
  <pre><code>NSDictionary *plainPart = [NSDictionary dictionaryWithObjectsAndKeys:@"text/plain",kSKPSMTPPartContentTypeKey,
  @"Hello,\n You've just received a new message from the iDHSB iPhone App.\n Here it is: %@",field.text,     
  kSKPSMTPPartMessageKey,@"8bit",kSKPSMTPPartContentTransferEncodingKey,nil];
  </code></pre>
  
  <p>...and I receive an NSException error saying;</p>
  
  <pre><code>*** WebKit discarded an uncaught exception in the webView:shouldInsertText:replacingDOMRange:givenAction: delegate:     
  &lt;NSInvalidArgumentException&gt; +[NSDictionary dictionaryWithObjectsAndKeys:]: second object of each pair must be non-nil.  Or, did  
  you forget to nil-terminate your parameter list?
  </code></pre>
  
  <p>What does this mean? What do I have to do to fix this issue?</p>
  
  <p>Thanks,</p>
  
  <p>James</p>