diff --git a/htdocs/propal.class.php b/htdocs/propal.class.php
index b9343d4f897..83b4811884e 100644
--- a/htdocs/propal.class.php
+++ b/htdocs/propal.class.php
@@ -34,6 +34,7 @@
 */
 
 require_once(DOL_DOCUMENT_ROOT ."/product.class.php");
+require_once(DOL_DOCUMENT_ROOT ."/contact.class.php");
 
 
 /**