Call to undefined method plugins::registerAction()

hi i have two error on ispconfig 3.0.4.6

PHP Warning: Invalid argument supplied for foreach() in /usr/local/ispconfig/server/lib/classes/monitor_tools.inc.php on line 1072

solution: add verif is_array() before the boucle

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PHP Fatal error: Call to undefined method plugins::registerAction() in /usr/local/ispconfig/server/plugins-available/backup_plugin.inc.php on line 54

solution for me, i commented the 2 lines who call this function...