Change <br> to <br /> 

Sub changebr()
  On Error Resume Next
  Dim objElements As IHTMLElementCollection
  Dim objElement As IHTMLElement
  Dim blnChanged As Boolean
  dim i as long
   
   For i = 0 To _
   Application.ActiveWeb.AllFiles.Count - 1
      strExt = Application.ActiveWeb. _
      AllFiles.Item(i).Extension
      If strExt = "htm" Then
        Application.ActiveWeb. _
        AllFiles.Item(i).Open
        Set objElements = _
        ActiveDocument.all.tags("body"). _
        Item(0).all.tags("br")
        
        For j = 0 To objElements.Length - 1
          Set objElement = objElements(j)
          blnChanged = True
          objElement.outerHTML = "<br />"
          intCount = intCount + 1
        Next j
          
        'Only save file if it has been changed.
        If blnChanged = True Then
          WebDesigner.ActivePageWindow.Save True
        End If
      End If
      WebDesigner.ActivePageWindow. _
      Close False, False

  Next i
End Sub