I am getting Overflow error message while running GetDesktopWindow.

Private Declare Function GetDesktopWindow Lib "user32" () As Long

Function StartDoc(DocName As String) As Integer
Dim Scr_hDC As Integer
Scr_hDC = GetDesktopWindow()
StartDoc = ShellExecute(20, "Open", DocName, "", "C:\", SW_SHOWNORMAL)
End Function

It works if I comment it out, but sometimes act strange.
Please help!