Last save time

[Mr Von]

Hello everybody,
sorry for my bad English. the 1st code works wonderfully. the 2nd code doesn't work. no error is displayed

Sub myMacro()
Dim strName As String
  strName = Application.UserName
  Application.UserName = InputBox("New last author")
  With ActiveWorkbook
    .BuiltInDocumentProperties("Last author") = Application.UserName
    .Save
  End With
  Application.UserName = strName
  ActiveWorkbook.Close
lbl_Exit:
  Exit Sub
End Sub

Sub myMacro()
Dim myDate As String
Dim strDate As String

  myDate = "2012-05-01 00:30:00"
  strDate = myDate
  
  With ActiveWorkbook
    .BuiltinDocumentProperties("Last save time") = CDate(strDate)
    .Save
  End With
  myDate = strDate
  ActiveWorkbook.Close
lbl_Exit:
  Exit Sub
End Sub

Please help, thank you