changed the code to:

Private Sub MapFrm_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Closed
ntMap.ActiveMap.SaveAs(Environment.CurrentDirector y & "\test.ptm", MapPoint.GeoSaveFormat.geoFormatMap, False)
ntMap.ActiveMap.Saved = True

End Sub

still no luck.

marc