/**
  * build the global Error object, read the configuration and check if all files are available
  * for a minimalistic function of the plugin
  *
  * @param String $plugin_name name of the plugin
  * @param String $enc         target encoding
  *
  * @return void
  */
 public function __construct($plugin_name, $enc)
 {
     $this->global_error = PSI_Error::Singleton();
     if (trim($plugin_name) != "") {
         $this->_plugin_name = $plugin_name;
         $this->_plugin_base = APP_ROOT . "/plugins/" . strtolower($this->_plugin_name) . "/";
         $this->_checkfiles();
         $this->_getconfig();
     } else {
         $this->global_error->addError("__construct()", "Parent constructor called without Plugin-Name!");
     }
     $this->_createXml($enc);
 }