Permission problem encountered with xmlHTTPrequests in Windows Vista using javascript.

(1) The current problem occurs in an HTA designed to publish information to and request information from a corporate web server.
(2) The current xmlHTTPrequest is written in javascript (below).
(3) When run under Windows XP Professional Service Pack 2, no problem exists.
(4) When tested on Windows Vista Ultimate x64 Service Pack 1, a permission error appears.
(5) The line where the permission error occurs is--

var objHTTP= new ActiveXObject("Msxml2.XMLHTTP");


CODE EXCERPT:

            function GetUpdateSD()
            {
                  var objHTTP = new ActiveXObject("Msxml2.XMLHTTP");
                  var strURL = TOC_SD_UPDATEURL + "&" + getClientID() + "&" + generateSID() + "&";
                  objHTTP.open('GET',strURL,xmlHTTPreqAsynchronous);
                  objHTTP.onreadystatechange=xmlHTTPrequestHandler_updateSD;
                  objHTTP.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
                  objHTTP.send(null);
            }