IXMLDOMDocument.load and IXMLDOMDocument.loadXML not work in VC++.

Dear all,
I have a xml file called metadata.xml. Now I would like to load it to an
IXMLDOMDocument variable. I have used both load and loadXML method of
IXMLDOMDocument (both have only one parametter) but they donot work. Does
any one have any ideas.Pls help me, show me in detail how to do it.
Thanks.