ok, in the Form.xml file, the FILE token should look like below.. all tags are case-sensitive. Also make sure you don't have a file named Form.xml in /portals/#/RepositoryTemplates/articles. Any template files in the Portals folder structure will override those in the /DesktopModules/Repository/Templates location with the same name.  I'm just in the process of installing 4.3.2, so I haven't been able to test this specifically on that version of DNN, but I will try and do that tomorrow and let you know.

 <Object>
  <Token>[FILE]</Token>
  <Settings>
   <Setting>
    <Name>Required</Name>
    <Value>false</Value>
   </Setting>
  </Settings>
 </Object>