Database Software

Hello, I have to write a secure website call and below is the code snippet. I am getting following error

ORA-31013: Invalid XPATH expression
ORA-06512: at "SYS.XMLTYPE", line 0
ORA-06512: at line 104

This is on Oracle9i Enterprise Edition Release 9.2.0.6.0 - 64bit Production

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Code snippet

soap_request :=
'<?xml version="1.0" encoding="utf-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<NewOrder xmlns="urn:ws.xtech.net/xtechGateway">
<newOrderRequest xsi:type="ns1:NewOrderRequestElement" xmlns:ns1="urn:ws.xtech.net/xtechGateway" xmlns="">
<ns1:xConnectionUsername>'
|| 'XXXXXXXX'
|| '</ns1:xConnectionUsername>';

UTL_HTTP.SET_WALLET ( 'file:/devdb/9.2.0/appsutil/wallet', 'password' );
http_req :=
UTL_HTTP.begin_request
('https://wsvar.xtech.net/xtechGateway',
'POST',
'HTTP/1.1'
);
UTL_HTTP.set_header (http_req, 'Content-Type', 'text/xml');
UTL_HTTP.set_header (http_req, 'Content-Length', LENGTH (soap_request));
utl_http.set_header(http_req, 'SOAPAction', '');
UTL_HTTP.write_text (http_req, soap_request);
http_resp := UTL_HTTP.get_response (http_req);
UTL_HTTP.read_text (http_resp, soap_respond);
UTL_HTTP.end_response (http_resp);
*resp := XMLTYPE.createxml (soap_respond);
resp :=
resp.EXTRACT
('/soap:Envelope/soap:Body/child::node()',
'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"'
);
v_resp :=
resp.EXTRACT ('NewOrderResponse/return/text ()', '"approvalStatus"').getstringval
();*

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Not sure where Am I doing wrong. Please help

Thanks,
R