That's not going to work ... as you have found. Try the following instead.
Code:
Sub UpdateDocuments()
Dim strInFolder As String, strOutFold As String, strFile As String
Dim wdDoc As Document
Dim hLink As Hyperlink
Dim sAddress As String, sDisplay As String, sTip As String
Application.ScreenUpdating = False
strInFolder = GetFolder
If strInFolder = "" Then Exit Sub
strFile = Dir(strInFolder & "\*.doc*", vbNormal)
'Check for documents in the folder - exit if none found
If strFile <> "" Then strOutFold = strInFolder & "\Output\"
'Test for an existing outpfolder & create one if it doesn't already exist
If Dir(strOutFold, vbDirectory) = "" Then MkDir strOutFold
strFile = Dir(strInFolder & "\*.doc*", vbNormal)
While strFile <> ""
Set wdDoc = Documents.Open(FileName:=strInFolder & "\" & strFile, AddToRecentFiles:=False, ReadOnly:=True, Visible:=False)
For Each hLink In wdDoc.Hyperlinks
With hLink
sAddress = .Address
If InStr(1, LCase(sAddress), "www.yahoo.com") > 0 Then
.Target = Replace(LCase(.Target), "www.yahoo.com", "www.google.com")
.Address = Replace(LCase(.Address), "www.yahoo.com", "www.google.com")
.TextToDisplay = Replace(LCase(.TextToDisplay), "www.yahoo.com", "www.google.com")
.ScreenTip = "Click to search"
End If
End With
Next hLink
Next hLink
'Save and close the document
wdDoc.SaveAs FileName:=strOutFold & wdDoc.Name, AddToRecentFiles:=False
wdDoc.Close
strFile = Dir()
Wend
Set wdDoc = Nothing
Application.ScreenUpdating = True
End Sub