Error install Kunena forum

Hello

Error install kunena forum

Message:
Disculpe, la instalación ha fallado a causa de los siguientes errores:
Notice: Use of undefined constant KPATH_ADMIN - assumed 'KPATH_ADMIN' in /home/policiasnacionales/www/administrator/components/com_kunena/install/schema.php on line 12 Notice: Use of undefined constant KPATH_ADMIN - assumed 'KPATH_ADMIN' in /home/policiasnacionales/www/administrator/components/com_kunena/install/schema.php on line 13 Warning: DOMDocument::load(): I/O warning : failed to load external entity "/home/policiasnacionales/www/administrator/KPATH_ADMIN/install/install.xml" in /home/policiasnacionales/www/administrator/components/com_kunena/install/schema.php on line 206 Notice: Trying to get property of non-object in /home/policiasnacionales/www/administrator/components/com_kunena/install/schema.php on line 281 Warning: Invalid argument supplied for foreach() in /home/policiasnacionales/www/administrator/components/com_kunena/install/schema.php on line 296 Fatal error: Class 'KunenaRoute' not found in /home/policiasnacionales/www/administrator/components/com_kunena/install/sql/install/php/sampledata.php on line 147

Help plis

Thank's