diff --git a/harbour/ChangeLog b/harbour/ChangeLog
index 9035fbe24a..ff0ab7bc85 100644
--- a/harbour/ChangeLog
+++ b/harbour/ChangeLog
@@ -16,6 +16,14 @@
    The license applies to all entries newer than 2009-04-28.
 */
 
+2012-01-31 00:56 UTC+0100 Przemyslaw Czerpak (druzus/at/poczta.onet.pl)
+  * harbour/contrib/gtwvg/wvgwin.c
+    ! added workaround for possible HVM string corruption and GPF in
+      WVG_SENDMESSAGE() function. This function is still very danger
+      when it's used with messages extracting data to passed buffer
+      and user have to pass string large enough to avoid possible
+      buffer overflow.
+
 2012-01-31 00:37 UTC+0100 Przemyslaw Czerpak (druzus/at/poczta.onet.pl)
   * harbour/contrib/gtwvg/wvgwin.c
     ! fixed wrongly used string handler instead of string pointer as
diff --git a/harbour/contrib/gtwvg/wvgwin.c b/harbour/contrib/gtwvg/wvgwin.c
index 8d6fc5f6fb..d7ebb0fd4c 100644
--- a/harbour/contrib/gtwvg/wvgwin.c
+++ b/harbour/contrib/gtwvg/wvgwin.c
@@ -125,7 +125,11 @@ static HINSTANCE wvg_hInstance( void )
 HB_FUNC( WVG_SENDMESSAGE )
 {
    void * hText = NULL;
-   LPTSTR lpText = HB_PARSTR( 4, &hText, NULL );
+   HB_SIZE nLen = 0;
+   LPCTSTR lpText = HB_PARSTR( 4, &hText, &nLen );
+
+   if( lpText && HB_ISBYREF( 4 ) )
+      lpText = HB_STRUNSHARE( &hText, lpText, nLen );
 
    hb_retnl( ( HB_ULONG ) SendMessage( ( HWND ) ( HB_PTRDIFF ) hb_parnint( 1 ),
                                        ( UINT ) hb_parni( 2 ),