Object required: 'objNode' , selectSingleNode problem

Hi I have a problem with some ASP/XML code. I have searched the web and found several other posts with the same problem but cant seem to find a solution anywhere.

The error :

Microsoft VBScript runtime error '800a01a8'
Object required: 'objNode'
/include/gettitlelist.inc.asp, line 231


The code:
'Get the value from an element in the data
Function getElementText(objXML, strXPath)
Dim objNode
Set objNode = objXML.selectSingleNode(strXPath)
getElementText = objNode.text 'line 231
Set objNode = Nothing
End Function

I have no XML experience so I have no Idea what is wrong. And the error only occurs when the users do a large search ??
Any guidance will be much apprieciated.

Let me know please.
Thanks

What happens when you remove the line:
Set objNode = Nothing
?