不能生效, 錯在何處?

Option Compare Database
 Private Declare Function GetLastInputInfo Lib "user32" (plii As LASTINPUTINFO) As Boolean
 Private Declare Function GetTickCount Lib "kernel32" () As Long
 Private Type LASTINPUTINFO
        cbSize  As Long
        dwTime  As Long
 End Type
 Dim lii   As LASTINPUTINFO
 Dim zjs, djs
 Dim msgcount As Integer
 Private Sub Form_Timer()
 Dim mytime   As Double
   lii.cbSize = Len(lii)
   GetLastInputInfo lii
   mytime = GetTickCount - lii.dwTime
   Debug.Print mytime & "ms"
   zjs = mytime \ 1000
   djs = 30 - zjs
   Me.Text1 = "離系統關閉時間:" & djs
   If djs = 0 Then
  Quit
   End If
 End Sub