diff --git a/htdocs/core/class/html.formaccounting.class.php b/htdocs/core/class/html.formaccounting.class.php
index 5fd67659e15..aaae010c2fe 100644
--- a/htdocs/core/class/html.formaccounting.class.php
+++ b/htdocs/core/class/html.formaccounting.class.php
@@ -24,6 +24,7 @@
  *  \ingroup    Advanced accountancy
  *	\brief      File of class with all html predefined components
  */
+require_once DOL_DOCUMENT_ROOT .'/core/class/html.form.class.php';
 
 
 /**