使用Ajax的时候出现的异常,请告诉我该异常出现的可能原因:oracle.xml.parser.v2.XMLParseException

oracle.xml.parser.v2.XMLParseException: Start of root element expected.
at oracle.xml.parser.v2.XMLError.flushErrors(XMLError.java:148)
at oracle.xml.parser.v2.NonValidatingParser.parseRootElement(NonValidatingParser.java:292)
at oracle.xml.parser.v2.NonValidatingParser.parseDocument(NonValidatingParser.java:254)
at oracle.xml.parser.v2.XMLParser.parse(XMLParser.java:221)
at parim.net.novartis.db.SystemVariable.load(SystemVariable.java:43)
at parim.net.novartis.db.SystemVariable.goToElement(SystemVariable.java:61)
at parim.net.novartis.db.SystemVariable.getProperty(SystemVariable.java:91)
at parim.net.novartis.db.MDBOper.connect(MDBOper.java:84)
at parim.net.novartis.db.MDBOper.getResultSet(MDBOper.java:158)
at parim.net.novartis.news.dao.main.GetNewsList.getNewsBy(GetNewsList.java:106)
at org.apache.jsp.jsp.main.ajaxInfo_jsp._jspService(ajaxInfo_jsp.java:95)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at parim.net.novartis.util.Charencode.doFilter(Charencode.java:24)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)