Ok I investigated further this one works across paths harddrives etc. If you have the rights you can do it
[VBA]
Sub SetHiddenBit(filespec As String, PathToFile As String)
Dim fs As FileSystemObject
Dim f As File
Dim p As Folder
Set fs = CreateObject("Scripting.FileSystemObject")
Set p = fs.GetFolder(PathToFile)
Set f = p.Files(filespec)
f.Attributes = 2
Set f = Nothing
Set p = Nothing
Set fs = Nothing
End Sub
Sub SendFile()
Dim FilNm As String
FilNm = "usat1.dwg"
SetHiddenBit FilNm, "c:\acad\"
End Sub
[/VBA]