php error opencart

[Fri Feb 19 22:35:32.589155 2016] [:error] [pid 1181] [client 172.17.1.131:54360] PHP Fatal error:  Call to a member function login() on a non-object in /var/www/html/catalog/controller/account/login.php on line 245, referer: http://testshop.test.lan/index.php?route=account/login

De code die op lijn 245 staat is: $this->user->login($this->request->post['email'], $password);