title: Installation of Opera Extension fails?
body: <p>I am trying to install self-built extension for Opera .
  As Opera suggests :</p>
  
  <p>1.One method is simply dragging .xml file to opera.And it gets installed in developer mode.
   Also it works pretty fine in my case.</p>
  
  <p>But the second method: </p>
  
  <p>2.Zip the folder and change name from .zip to .oex. Now drag it to Opera.</p>
  
  <p>And it gets installed.This doesn't work. </p>
  
  <p>I get the following popups</p>
  
  <p><img src="https://i.stack.imgur.com/JnB93.png" alt="get this popup"></p>
  
  <p>And when I click OK.I get the following message.
  <img src="https://i.stack.imgur.com/vkeML.png" alt="enter image description here"></p>
  
  <p>Anyone can tell me what is the problem.</p>
  
  <p>Still the First method works completely fine.    And the Extension is also working fine.</p>