diff --git a/lib/common.php b/lib/common.php
index 2f85eb7c51..041459cf34 100644
--- a/lib/common.php
+++ b/lib/common.php
@@ -53,6 +53,7 @@ require_once(INSTALLDIR.'/lib/language.php');
 // can use it
 
 require_once(INSTALLDIR.'/lib/event.php');
+require_once(INSTALLDIR.'/lib/plugin.php');
 
 // try to figure out where we are