oracle 31011,ORA-31011: XML parsing failed

Hi.

I parse XML file by the follow sql statements:

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DECLARE

V_XML_PARSER XMLPARSER.PARSER;

V_REQUEST_DATA CLOB;

BEGIN

V_XML_PARSER := XMLPARSER.NEWPARSER;

SELECT REQUEST_DATA

INTO V_REQUEST_DATA ---GET THE CLOB DATA

FROM APPS.XXXXX

WHERE PROCESS_SN='xxxxxxxxxxx';

XMLPARSER.PARSECLOB(V_XML_PARSER, V_REQUEST_DATA);

END;

---------------------------------------------------------------------------------------------

and it shows the following errors:

ORA-31011: XML parsing failed

ORA-19202: Error occurred in XML processing

LPX-00217: invalid character 189 (U+00BD)

Error at line 1

ORA-06512: at "XDB.DBMS_XMLPARSER", line 191

ORA-06512: at line 12

What causes these errors?

Thanks.