title: Warning: implode() [function.implode]: Invalid arguments passed in ... on line 50
body: <pre><code>class  plgSystemUnpublishfront extends JPlugin
  {
      /**
       * Constructor
       *
       * For php4 compatability we must not use the __constructor as a constructor for plugins
       * because func_get_args ( void ) returns a copy of all passed arguments NOT references.
       * This causes problems with cross-referencing necessary for the observer design pattern.
       *
       * @param   object      $subject The object to observe
        * @param  array       $config  An array that holds the plugin configuration
       * @since   1.0
       */
      function plgSystemUnpublishfront(&amp; $subject, $config)
      {
          parent::__construct($subject, $config);
      }
  
      /**
       * Fixes the $my global if the user was restored by the remember me plugin
       */
      function onAfterInitialise()
      {
          $days       = $this-&gt;params-&gt;get('days');
          $startpoint = $this-&gt;params-&gt;get('startpoint');
          $excludes   = $this-&gt;params-&gt;get('excludes',0);
  
          $db = &amp; JFactory::getDBO();
  
          $query = "SELECT id FROM #__content AS"
          ."\n WHERE DATE_ADD($startpoint, INTERVAL $days DAY) &lt; NOW() AND id NOT IN($excludes)";
          $db-&gt;setQuery($query);
          $rows = $db-&gt;loadResultArray();
  
          $daystring = implode(',' , $rows);
  
          $query = "DELETE FROM #__content_frontpage WHERE content_id IN($daystring)";
          $db-&gt;setQuery($query);
          $db-&gt;Query();
      }
  }
  **line 50 is "$daystring = implode(',' , $rows);"**
  </code></pre>
  
  <p>so where is the mistake?</p>