diff --git a/main/webservices/courses_list.soap.php b/main/webservices/courses_list.soap.php
index f238fde5e7..918427ece2 100755
--- a/main/webservices/courses_list.soap.php
+++ b/main/webservices/courses_list.soap.php
@@ -60,6 +60,7 @@ function DokeosWSCourseList($username, $signature, $visibilities='public') {
 	if (empty($username) or empty($signature)) { return -1; }
 
     require_once (api_get_path(LIBRARY_PATH).'course.lib.php');
+    require_once (api_get_path(LIBRARY_PATH).'usermanager.lib.php');
     global $_configuration;
     
     $info = api_get_user_info_from_username($username);