force loading of encryption app

apps/files_encryption/files/error.php

@@ -4,6 +4,9 @@ if (!isset($_)) { //also provide standalone error page
 	require_once __DIR__ . '/../../../lib/base.php';
 	require_once __DIR__ . '/../lib/crypt.php';
 
+	OC_JSON::checkAppEnabled('files_encryption');
+	OC_App::loadApp('files_encryption');
+
 	$l = \OC::$server->getL10N('files_encryption');
 
 	if (isset($_GET['errorCode'])) {