ASP startpoint when parsing xml

Hi
I am trying to get the results from an amazon xml feed using asp/ xml the following code works but only if the start point is valid. the startpoint is looking for <OurPrice> but if the product is not in stock the <OurPrice> attribute is not returned through the xml so my script crashes, what I need it to do is if the startpoint <OurPrice> is not returned set the value of strPrice to '0.00', the variable strPrice is then being used in an update statement to set the price in my database.  I would like to try and get an answer in classic asp please,

here is the code

 I'm using, I have taken out my developer token so the link to amazon will crash in this example

Dim objXML
             Set objXML = Server.CreateObject("MSXML2.ServerXMLHTTP.6.0")
                  strURL ="http://xml-eu.amazon.com/onca/xml3?t=webservices-20&dev-t=&AsinSearch=B0009yjb1g&type=lite&page=1&locale=uk&f=xml"
                  objXML.Open "GET" , strURL , False ,"",""
            objXML.Send
              If objXML.Status = 200 then
          strOpen = objXML.ResponseText
                            vStartAt1 = 1
          do while vStartAt1 <> -1
        startPoint= InStr(vStartAt1, strOpen, "<OurPrice>")   'Look for start string, start looking from cursor location.
'========================
If startPoint = 0 or IsNull(startPoint) then
   exit do
end if
'========================
     if startPoint <> -1 then  
          endPoint = InStr(startPoint, strOpen, "</OurPrice>")
                 if endPoint <> -1 then
             strPrice = Mid(strOpen, startPoint, endPoint-startPoint)
                   strPrice = Replace(strPrice, "'", """")
                    strPrice = Replace(strPrice, "<OurPrice>", "")
                    strPrice = Replace(strPrice, "£", "")
                       
                        Set db1 = server.CreateObject("ADODB.Connection")
db1.open MM_luxurygifts_STRING
strSQL1 = "UPDATE dbo.thomas SET pricecheckstatus = '2', pricecheck = (" & strPrice & ") FROM thomas WHERE id=151"
set rs1 = db1.execute(strSQL1)
set rs1 = nothing
db1.close
set db1 = nothing
            Else
           end if
             vStartAt1 = endPoint
              end if
                                  loop
                                      End if
        Set objXML = Nothing