diff --git a/harbour/ChangeLog.txt b/harbour/ChangeLog.txt
index 1cea9c20b5..6b0153cb4b 100644
--- a/harbour/ChangeLog.txt
+++ b/harbour/ChangeLog.txt
@@ -10,6 +10,10 @@
      * Change, ! Fix, % Optimization, + Addition, - Removal, ; Comment
  */
 
+2013-01-28 17:53 UTC+0100 Przemyslaw Czerpak (druzus/at/poczta.onet.pl)
+  * harbour/src/vm/classes.c
+    ! added missing HB_STACK_TLS_PRELOAD
+
 2013-01-28 17:44 UTC+0100 Przemyslaw Czerpak (druzus/at/poczta.onet.pl)
   * harbour/src/vm/classes.c
     + added new PRG function:
diff --git a/harbour/src/vm/classes.c b/harbour/src/vm/classes.c
index 0c722f1038..b36c6b9040 100644
--- a/harbour/src/vm/classes.c
+++ b/harbour/src/vm/classes.c
@@ -5147,6 +5147,7 @@ HB_FUNC( __CLSGETANCESTORS )
 
    if( uiClass && uiClass <= s_uiClasses )
    {
+      HB_STACK_TLS_PRELOAD
       PHB_ITEM pReturn = hb_stackReturnItem();
       PCLASS pClass = s_pClasses[ uiClass ];
       HB_SIZE nPos = 0;