Is there something wrong with my code (VB.Net Windows forms app)?

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

There is no file being saved anywhere to disk. Am I missing something?

Thanks!
Marc