It's only a matter of brackets..

Code:
Sub M_stttys()
    sn = Split(CreateObject("scripting.filesystemobject").opentextfile("G:\OF\__resto.txt").readall, vbCrLf)
    For j = 1 To 2
        c01 = c01 & vbLf & Join(Filter(sn, Choose(j, "Sent", "Subject")), vbLf)
    Next
    MsgBox c01
End Sub