diff --git a/src/www/vpn_openvpn_client.php b/src/www/vpn_openvpn_client.php
index d6f73c489..5125fccc2 100644
--- a/src/www/vpn_openvpn_client.php
+++ b/src/www/vpn_openvpn_client.php
@@ -31,6 +31,7 @@ require_once("guiconfig.inc");
 require_once("openvpn.inc");
 require_once("services.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 if (!isset($config['openvpn']['openvpn-client'])) {
     $config['openvpn']['openvpn-client'] = array();
diff --git a/src/www/vpn_openvpn_server.php b/src/www/vpn_openvpn_server.php
index 581d3f1f1..6c30e4697 100644
--- a/src/www/vpn_openvpn_server.php
+++ b/src/www/vpn_openvpn_server.php
@@ -31,6 +31,7 @@ require_once("guiconfig.inc");
 require_once("openvpn.inc");
 require_once("services.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 if (!isset($config['openvpn']['openvpn-server'])) {
     $config['openvpn']['openvpn-server'] = array();
diff --git a/src/www/wizard.php b/src/www/wizard.php
index de952e7d1..260ddca79 100644
--- a/src/www/wizard.php
+++ b/src/www/wizard.php
@@ -33,6 +33,7 @@ require_once("filter.inc");
 require_once("rrd.inc");
 require_once("system.inc");
 require_once("interfaces.inc");
+require_once("plugins.inc");
 
 /*
  * find_ip_interface($ip): return the interface where an ip is defined