Scheduler demo error

[tuzgSina]

in NT 4.0 ,tomcat3.1 it runs well,but when I change to linux, get this : Exception: java.lang.NullPointerException at org.apache.turbine.services.webmacro.TurbineWebMacroService.getContext(TurbineWebMacroService.java, Compiled Code) at org.apache.turbine.services.webmacro.TurbineWebMacro.getContext(TurbineWebMacro.java, Compiled Code) at org.apache.turbine.modules.pages.WebMacroSitePage.doBuild(WebMacroSitePage.java, Compiled Code) at org.apache.turbine.modules.Page.build(Page.java, Compiled Code) at org.apache.turbine.modules.PageLoader.exec(PageLoader.java, Compiled Code) at Turbine.doGet(Turbine.java, Compiled Code) at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code) at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code) at org.apache.tomcat.core.ServletWrapper.handleRequest(ServletWrapper.java, Compiled Code) at org.apache.tomcat.core.ServletWrapper.handleRequest(ServletWrapper.java, Compiled Code) at org.apache.tomcat.servlets.InvokerServlet.service(InvokerServlet.java, Compiled Code) at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code) at org.apache.tomcat.core.ServletWrapper.handleRequest(ServletWrapper.java, Compiled Code) at org.apache.tomcat.core.ContextManager.service(ContextManager.java, Compiled Code) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java, Compiled Code) at org.apache.tomcat.service.TcpConnectionThread.run(SimpleTcpEndpoint.java, Compiled Code) at java.lang.Thread.run(Thread.java, Compiled Code)