MSXML XPath question

["White, Solomon" <Solomon_White@amr-corp.com>]

Hello all--

I have a question regarding the use of XPath in IE5+.  What I am trying to
do is build an html page that loads xml data from a file, then gives users
the ability to filter/sort the data.  The way I am attempting to go about
this is as follows (see actual code below):

1) on page load, create MSXML2.DOMDocument object, load data, set selection
language of object to XPath.
2) Select all nodes ("/") into a "display" object
3) Loop through display object, creating rows/cells in an HTML table
4) When the user specifies a filter, reset display object to have only
selected records from original XML object, clear the table, then repeat step
3 to display only selected records.

This all works except step 4.  I do not get any errors, but all records are
displayed instead of the selection.  BTW, I tried my XPath query string in
an XPath validation page, and it validates correctly.

Any ideas?

------CODE SNIPPETS FOLLOW----
  //this code creates the necessary objects
  var oXML = new ActiveXObject("MSXML2.DOMDocument");
  oXML.async = false;
  oXML.validateOnParse=false;
  if (! oXML.load("test_small.xml")) {
    alert("unable to load test_small.xml");
  }
  oXML.setProperty("SelectionLanguage", "XPath");
  var oDisplay = oXML.selectNodes("/");

  function load_data() {
    //display all data in oDisplay in HTML table
    //empty the table
    while (tblXML.rows.length > 0) {
      tblXML.deleteRow();
    }

    //add XML content to table
    var root = oDisplay.context.firstChild;
    for (i=0; i<root.childNodes.length; i++) {
      var doc = root.childNodes(i);
      var oRow = tblXML.insertRow();
      for (j=0; j<doc.childNodes.length; j++) {
        var oCell = oRow.insertCell();
        oCell.innerHTML = doc.childNodes(j).xml;
      }
    }
  }

  function doFilter() {
    //oDisplay = oXML.selectNodes("/Index/document[starts-with(user,'J')]");
    oDisplay = oXML.selectNodes("/Index/document[user='Joe Blow']");
    load_data();
  }