Can't load node from .jdf file in Vbscript - object

Question

I'm trying to get a value from a node in a .jdf file.
It gives us an error
object required: 'curNode'
in line no. 13 - inputFolder = curNode.getAttribute("Amount")
We don't really know what to do... any help please?
Thank you
'creates the msxml object
Set xmlDoc = CreateObject("Msxml2.DOMDocument.6.0")
Dim xmlDataPath,retVal
xmlDataPath = "C:\Users\liatte\Desktop\Aviv Omer Neta\JDFs to Txt\a.jdf"
'load the xml data of the script
retVal=xmlDoc.load(xmlDataPath)
'get input folder
Set curNode = xmlDoc.selectSingleNode("//JDF/ResourceLinkPool/ComponentLink")
Dim inputFolder
inputFolder = curNode.getAttribute("Amount")

Answer 1

To deal with the error, check
If curNode Is Nothing Then
...
Else
Dim inputFolder
...
End If
Obviously your assumptions (XPath expression) about the source file are wrong, when selectSingleNode() fails.

Answer 2

If an XPath expression like //JDF/ResourceLinkPool/ComponentLink does not select elements in your input document then it is likely that you are processing a document which uses namespaces, see http://en.wikipedia.org/wiki/XML_namespaces.
With XPath 1.0 a path like /foo/bar selects bar child elements of foo elements in no namespace while with an XML document of the form
<foo xmlns="http://example.com/ns1">
<bar>baz</bar>
</foo>
the elements are in the namespace http://example.com/ns1.
With your sample there is probably a default namespace declaration (e.g. xmlns="http://www.CIP4.org/JDFSchema_1_1") which requires you to change your XPath expressions by defining a prefix for the namespace e.g.
xmlDoc.setProperty "SelectionNamespaces", "xmlns:jdf='http://www.CIP4.org/JDFSchema_1_1'"
and using it:
Set curNode = xmlDoc.selectSingleNode("//jdf:JDF/jdf:ResourceLinkPool/jdf:ComponentLink")
Documentation for MSXML is at http://msdn.microsoft.com/en-us/library/windows/desktop/ms756048%28v=vs.85%29.aspx.