DocumentBuilder.parse(URL) in Applet

Hi there,

I have got an applet from where I want to parse an xml document
located in a given url, but I am having problems with it. The code I
have is simple:

// assert permission
if (Class.forName("com.ms.security.PolicyEngine") != null)
    PolicyEngine.assertPermission(PermissionID.NETIO);

// parse the xml document
DocumentBuilderFactory docBuilderFactory;
DocumentBuilder docBuilder;
Document doc;

docBuilderFactory = DocumentBuilderFactory.newInstance();
docBuilder = docBuilderFactory.newDocumentBuilder();
doc = docBuilder.parse("http://somewhere/somearchive.xml");

And the error report I get from IE5.0 is:

java.lang.IllegalAccessError: com/sun/xml/tree/XmlDocument

Could anyone help me? 

Thanks in advance,
Marielle