diff --git a/include/class.format.php b/include/class.format.php
index cd9b27f24657c5c95ff59699d9706912c38ae36b..d824a4e38360f0e5dc58dba8c42c20698951096b 100644
--- a/include/class.format.php
+++ b/include/class.format.php
@@ -15,6 +15,7 @@
 **********************************************************************/
 
 include_once INCLUDE_DIR.'class.charset.php';
+require_once INCLUDE_DIR.'class.variable.php';
 
 class Format {