求助：空指针异常问题！急。

我建的是一个Web项目，在本机上测试没有异常！但发布Webservice之后，在另一个IP地址机上测试就
报出了如下错误 ：请问怎么解决！！！
java.lang.NullPointerException
        at com.unitedpacs.impl.report.RisstudiesImpl.selectm(RisstudiesImpl.java:423)
        at com.unitedpacs.webservices.ReportWS.selectm(ReportWS.java:49)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.xml.ws.api.server.InstanceResolver$1.invoke(InstanceResolver.java:246)
        at com.sun.xml.ws.server.InvokerTube$2.invoke(InvokerTube.java:146)
        at com.sun.xml.ws.server.sei.EndpointMethodHandler.invoke(EndpointMethodHandler.java:257)
        at com.sun.xml.ws.server.sei.SEIInvokerTube.processRequest(SEIInvokerTube.java:93)
        at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:598)
        at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:557)
        at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:542)
        at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:439)
        at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:243)
        at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:444)
        at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:244)
        at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:135)
        at com.sun.xml.ws.transport.http.servlet.WSServletDelegate.doGet(WSServletDelegate.java:129)
        at com.sun.xml.ws.transport.http.servlet.WSServletDelegate.doPost(WSServletDelegate.java:160)
        at com.sun.xml.ws.transport.http.servlet.WSServlet.doPost(WSServlet.java:75)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
        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 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(Thread.java:619)