网站运行一段时间后必须重启tomcat才能访问

用WINDOWS 2003 +tomcat 5.0，运行一段时间后总是提示无法访问必须要重启tomcat后网站才能访问，哪位大侠知道如何解决？在这里先谢谢，
tomcat日志如下：
2009-06-08 14:40:44 createObjectName with StandardEngine[Catalina].StandardHost[localhost]
2009-06-08 14:40:44 preRegister with Catalina:type=Logger,host=localhost
2009-06-08 14:40:45 ContextListener: contextInitialized()
2009-06-08 14:40:45 SessionListener: contextInitialized()
2009-06-08 14:40:45 ContextListener: contextInitialized()
2009-06-08 14:40:45 SessionListener: contextInitialized()
2009-06-08 14:40:45 StandardHost[localhost]: Error deploying application at context path null
java.lang.IllegalStateException: Context path  is already in use
        at org.apache.commons.digester.Digester.createSAXException(Digester.java:2540)
        at org.apache.commons.digester.Digester.createSAXException(Digester.java:2566)
        at org.apache.commons.digester.Digester.endElement(Digester.java:1061)
        at org.apache.xerces.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:585)
        at org.apache.xerces.impl.XMLNamespaceBinder.endElement(XMLNamespaceBinder.java:647)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1008)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1469)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:329)
        at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:525)
        at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:581)
        at org.apache.xerces.parsers.XMLParser.parse(XMLParser.java:152)
        at org.apache.xerces.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1175)
        at org.apache.commons.digester.Digester.parse(Digester.java:1567)
        at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:511)
        at org.apache.catalina.core.StandardHost.install(StandardHost.java:866)
        at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:523)
        at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:468)
        at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1002)
        at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:393)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:166)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
        at org.apache.catalina.core.StandardHost.start(StandardHost.java:792)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1125)
        at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:502)
        at org.apache.catalina.core.StandardService.start(StandardService.java:519)
        at org.apache.catalina.core.StandardServer.start(StandardServer.java:2343)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:392)