All the credit, for that part of the article from where you got the routine,
is due to Peter Hewett.  Here is the original post in which I first used the
code:

Here's something that should help (makes use of some code supplied by Peter
Hewett)

Public Sub BatchReplaceAnywhere()
Dim FirstLoop As Boolean
Dim myFile As String
Dim PathToUse As String
Dim myDoc As Document
Dim rngstory As Word.Range
Dim FindText As String
Dim Replacement As String
' Get the folder containing the files
With Dialogs(wdDialogCopyFile)
   If .Display <> 0 Then
       PathToUse = .Directory
   Else
       MsgBox "Cancelled by User"
       Exit Sub
   End If
End With
'Close any documents that may be open
If Documents.Count > 0 Then
   Documents.Close Savechanges:=wdPromptToSaveChanges
End If
FirstLoop = True
myFile = Dir$(PathToUse & "*.doc")
While myFile <> ""
   'Get the text to be replaced and the replacement
   If FirstLoop = True Then
       FindText = InputBox("Enter the text that you want to replace.",
"Batch Replace Anywhere")
       Replacement = InputBox("Enter the replacement text.", "Batch Replace
Anywhere ")
       FirstLoop = False
   End If
   'Open each file and make the replacement
   Set myDoc = Documents.Open(PathToUse & myFile)
   ' Fix the skipped blank Header/Footer problem
   MakeHFValid
   ' Iterate through all story types in the current document
   For Each rngstory In ActiveDocument.StoryRanges
       ' Iterate through all linked stories
       Do
           SearchAndReplaceInStory rngstory, FindText, Replacement
           ' Get next linked story (if any)
           Set rngstory = rngstory.NextStoryRange
       Loop Until rngstory Is Nothing
   Next
   'Close the file, saving the changes.
   myDoc.Close Savechanges:=wdSaveChanges
   myFile = Dir$()
Wend
End Sub

Public Sub SearchAndReplaceInStory(ByVal rngstory As Word.Range, _
                                  ByVal strSearch As String, _
                                  ByVal strReplace As String)
'This routine supplied by Peter Hewett
   Do Until (rngstory Is Nothing)
       With rngstory.Find
           .ClearFormatting
           .Replacement.ClearFormatting
           .Text = strSearch
           .Replacement.Text = strReplace
           .Forward = True
           .Wrap = wdFindContinue
           .Format = False
           .MatchCase = False
           .MatchWholeWord = False
           .MatchAllWordForms = False
           .MatchSoundsLike = False
           .MatchWildcards = False
           .Execute Replace:=wdReplaceAll
       End With
      Set rngstory = rngstory.NextStoryRange
   Loop
End Sub

Public Sub MakeHFValid()
'And this too
   Dim lngJunk As Long
   ' It does not matter whether we access the Headers or Footers property.
   ' The critical part is accessing the stories range object
   lngJunk = ActiveDocument.Sections(1).Headers(1).Range.StoryType
End Sub