diff --git a/htdocs/core/class/conf.class.php b/htdocs/core/class/conf.class.php
index 7fdd4ac5731..ca15812b1fa 100644
--- a/htdocs/core/class/conf.class.php
+++ b/htdocs/core/class/conf.class.php
@@ -1,7 +1,7 @@
 <?php
 /* Copyright (C) 2003-2007 Rodolphe Quiedeville <rodolphe@quiedeville.org>
  * Copyright (C) 2003      Xavier Dutoit        <doli@sydesy.com>
- * Copyright (C) 2004-2011 Laurent Destailleur  <eldy@users.sourceforge.net>
+ * Copyright (C) 2004-2012 Laurent Destailleur  <eldy@users.sourceforge.net>
  * Copyright (C) 2005-2012 Regis Houssin      	<regis@dolibarr.fr>
  * Copyright (C) 2006 	   Jean Heimburger    	<jean@tiaris.info>
  *
@@ -160,6 +160,7 @@ class Conf
 							$modulename = strtolower($reg[1]);
 							$partname = strtolower($reg[2]);
 							$varname = $partname.'_modules';
+							$this->$varname = array();
 							$arrValue = unserialize($value);
 							if (is_array($arrValue) && ! empty($arrValue)) $value = $arrValue;
 							else $value = ($value == 1 ? '/'.$modulename.'/core/'.$partname.'/' : $value);