You can use the InStrRev function as follows:
Code:
   Dim iSeparatorPos As Integer
   Dim sFullPath As String
   Dim sSubDir As String
   
   sFullPath = Mailouts.SelectedFolder
   
   If Right(sFullPath, 1) = "\" Then
      sFullPath = Mid(sFullPath, 1, Len(sFullPath) - 1)
   End If
   
   iSeparatorPos = InStrRev(sFullPath, "\")
   
   If iSeparatorPos > 0 Then
      sSubDir = Mid(sFullPath, iSeparatorPos + 1)
   Else
      sSubDir = sFullPath
   End If
   
   Call MsgBox(sSubDir)
Hope this is what you were looking for.