title: What does this error actually mean?
body: <p>So I have seen this error show up, just sometimes, but it is not helpful in describing the actual error which has occured. Nor does it give any clues as to what might cause it to display.</p>
  
  <p><code>Cannot use modParams with indexes that do not exist.</code></p>
  
  <p>Can anyone explain more verbosly what this error means, what it relates to (such as a behaviour, component, controller, etc), the most common causes and how to fix it?</p>
  
  <p>To kickstart the investigation, you can find the error here.
  <a href="https://github.com/cakephp/cakephp/blob/master/lib/Cake/Utility/ObjectCollection.php#L128" rel="nofollow">https://github.com/cakephp/cakephp/blob/master/lib/Cake/Utility/ObjectCollection.php#L128</a></p>