diff --git a/presentation/lookAndFeel/knowledgeTree/documentmanagement/viewBL.php b/presentation/lookAndFeel/knowledgeTree/documentmanagement/viewBL.php
index 9b7b3d1..03d0139 100644
--- a/presentation/lookAndFeel/knowledgeTree/documentmanagement/viewBL.php
+++ b/presentation/lookAndFeel/knowledgeTree/documentmanagement/viewBL.php
@@ -43,6 +43,8 @@ require_once("$default->fileSystemRoot/lib/visualpatterns/PatternCustom.inc");
 require_once("$default->fileSystemRoot/lib/visualpatterns/PatternListFromQuery.inc");
 require_once("$default->fileSystemRoot/lib/visualpatterns/PatternTableSqlQuery.inc");
 
+require_once("$default->fileSystemRoot/lib/subscriptions/Subscription.inc");
+
 require_once("$default->fileSystemRoot/presentation/lookAndFeel/knowledgeTree/documentmanagement/documentUI.inc");
 require_once("$default->fileSystemRoot/presentation/lookAndFeel/knowledgeTree/documentmanagement/viewUI.inc");
 require_once("$default->fileSystemRoot/presentation/lookAndFeel/knowledgeTree/foldermanagement/folderUI.inc");