XML : RunTime Error 91 - XML object variable not set. Works half the time?

I have a VB script that opens an XML document and pulls some information from it.

  Function fnReadXMLByTags(address As String) As String  ' Part of of adapted from http://excel-macro.tutorialhorizon.com/vba-excel-read-data-from-xml-file/  Dim mainWorkBook As Workbook  Dim mainWS  As Worksheet  Dim addressArray()  Dim addressArrayLen As Integer  Dim tempi As Integer  Dim latitude As Double, longitude As Double  Dim county As String, altAddress As String    'Let's add the addresses to look up into our array:  lastRow = Cells(50000, 1).End(xlUp).row  If lastRow > 1 Then      addressArray() = Range(Cells(1, 1), Cells(lastRow, 1))  Else      addressArray() = Range(Cells(1, 1), Cells(2, 1))  End If  addressArrayLen = UBound(addressArray) - LBound(addressArray) + 1    Set mainWorkBook = ActiveWorkbook  Set mainWS = Sheets("Sheet1")  mainWS.Range("A:A").Clear  Set oXMLFile = CreateObject("Microsoft.XMLDOM")    Dim startRow As Integer, adrRow As Integer  startRow = Cells(50000, 1).End(xlUp).row      For k = LBound(addressArray) To UBound(addressArray)        If addressArray(k, 1) = "" Then Exit For      strAddress = addressArray(k, 1)    ' URLEncode(Address)      'Assemble the query string      strQuery = "http://maps.googleapis.com/maps/api/geocode/xml?"      strQuery = strQuery & "address=" & strAddress      strQuery = strQuery & "&sensor=false"      Debug.Print strQuery      XMLFileName = strQuery        oXMLFile.async = False      oXMLFile.Load (XMLFileName)        Set latitudenodes = oXMLFile.SelectNodes("/GeocodeResponse/result/geometry/location/lat/text()")      Set LongitudeNodes = oXMLFile.SelectNodes("/GeocodeResponse/result/geometry/location/lng/text()")      Set addressNodes = oXMLFile.SelectNodes("/GeocodeResponse/result/formatted_address/text()")      Set countyNodes = oXMLFile.SelectNodes("/GeocodeResponse/result/address_component[type='administrative_area_level_2']/long_name/text()")      Dim totalCoords As Integer        With mainWS          .Range(.Cells(startRow, 1), .Cells(startRow, 4)).Interior.ColorIndex = 40          .Range(.Cells(startRow, 1), .Cells(startRow, 4)).Borders.Value = 1          .Range("A" & startRow).Value = "Lookup Address: " & strAddress          .Range("B" & startRow).Value = "Latitude"          .Range("C" & startRow).Value = "Longitude"          .Range("D" & startRow).Value = "Total Coordinates: " & latitudenodes.Length          If latitudenodes.Length = 0 And addressNodes.Length = 0 And countyNodes.Length = 0 Then              mainWS.Cells(startRow + 1, 1).Value = "No such address found for '" & strAddress & "'"          End If          For i = 0 To (latitudenodes.Length - 1)              tempi = i              latitude = latitudenodes(i).NodeValue              longitude = LongitudeNodes(i).NodeValue              altAddress = addressNodes(i).NodeValue              county = countyNodes(i).NodeValue ' THIS IS THE LINE THAT THROWS THE ERROR!!!!!!-----------                i = .Cells(40000, 1).End(xlUp).row + 1              .Range(.Cells(i, 2), .Cells(i, 3)).Borders.Value = 1              .Range("B" & i).Value = latitude              .Range("C" & i).Value = longitude              .Range("A" & i).Value = altAddress              .Range("E" & i).Value = county              i = tempi          Next i            lastRow = .Cells(1, 1).End(xlDown).row          If lastRow = 1048576 Then lastRow = 2        End With                 'End the With mainWS        startRow = lastRow + 1  Next k    lastRow = mainWS.UsedRange.Rows.Count  For i = 2 To lastRow      If IsEmpty(mainWS.Cells(i, 4)) Then          mainWS.Cells(i, 4).FormulaR1C1 = "=HYPERLINK(""https://www.google.com/maps/place//@""&RC[-2]&"",""&RC[-1]&"",16z/data=!3m1!4b1!4m2!3m1!1s0x0:0x0"",""Link"")"      End If  Next i    End Function    

If I have a list of addresses in column A, this macro runs fine for many of the addresses...however, after some point (seems to be when i >= 28), when trying to set county = countyNodes(i).NodeValue I get the error "Object variable or With block not set".

How come? It doesn't do this for any of the other things (latitude,longitude,altAddress). Methinks it's to do with the actual XML...

Thanks for any ideas!

Edit: Here's an XML page that, when loaded, contributes to the error: Link

There are administrative_area_level_2 tags in there, for each location. (Ugh! Now I notice that the county isn't pulling the right county..hmm)