dwr部署到weblogic上的问题

在tomcat5.0.28上部署成功，但在weblogic8.1上出现一下异常：
007-03-16 10:09:57,781 FATAL - Rethrowing Error:java.lang.ExceptionInInitialize
rError

java.lang.NullPointerException
        at java.util.Hashtable.get(Hashtable.java:333)
        at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactory
Impl.java:233)
        at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactory
Impl.java:209)
        at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
        at org.directwebremoting.util.CommonsLoggingOutput.<init>(CommonsLogging
Output.java:35)
        at org.directwebremoting.util.Logger.<init>(Logger.java:62)
        at org.directwebremoting.util.Logger.getLogger(Logger.java:33)
        at org.directwebremoting.annotations.AnnotationsConfigurator.<clinit>(An
notationsConfigurator.java:329)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct
orAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC
onstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
        at java.lang.Class.newInstance0(Class.java:308)
        at java.lang.Class.newInstance(Class.java:261)
        at org.directwebremoting.impl.ContainerUtil.configureFromAnnotations(Con
tainerUtil.java:306)
        at org.directwebremoting.impl.ContainerUtil.configureContainerFully(Cont
ainerUtil.java:402)
        at org.directwebremoting.servlet.DwrServlet.init(DwrServlet.java:77)
        at weblogic.servlet.internal.ServletStubImpl$ServletInitAction.run(Servl
etStubImpl.java:1028)
        at weblogic.security.acl.internal.AuthenticatedSubject.doAs(Authenticate
dSubject.java:321)
        at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:
121)
        at weblogic.servlet.internal.ServletStubImpl.createServlet(ServletStubIm
pl.java:904)
        at weblogic.servlet.internal.ServletStubImpl.createInstances(ServletStub
Impl.java:883)
        at weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubI
mpl.java:822)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlet(WebAppS
ervletContext.java:3333)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlets(WebApp
ServletContext.java:3290)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlets(WebApp
ServletContext.java:3276)
        at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAp
pServletContext.java:3259)
        at weblogic.servlet.internal.WebAppServletContext.setStarted(WebAppServl
etContext.java:5949)
        at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:862)
        at weblogic.j2ee.J2EEApplicationContainer.start(J2EEApplicationContainer
.java:2127)
        at weblogic.j2ee.J2EEApplicationContainer.activate(J2EEApplicationContai
ner.java:2168)
        at weblogic.j2ee.J2EEApplicationContainer.activate(J2EEApplicationContai
ner.java:2115)
        at weblogic.management.deploy.slave.SlaveDeployer$Application.setActivat
ion(SlaveDeployer.java:3082)
        at weblogic.management.deploy.slave.SlaveDeployer.setActivationStateForA
llApplications(SlaveDeployer.java:1751)
        at weblogic.management.deploy.slave.SlaveDeployer.resume(SlaveDeployer.j
ava:359)
        at weblogic.management.deploy.DeploymentManagerServerLifeCycleImpl.resum
e(DeploymentManagerServerLifeCycleImpl.java:229)
        at weblogic.t3.srvr.SubsystemManager.resume(SubsystemManager.java:131)
        at weblogic.t3.srvr.T3Srvr.resume(T3Srvr.java:966)
        at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:361)
        at weblogic.Server.main(Server.java:32)
<2007-3-16 上午10时09分58秒 CST> <Error> <HTTP> <BEA-101216> <Servlet: "dwr-invo
ker" failed to preload on startup in Web application: "yys".
javax.servlet.ServletException
        at org.directwebremoting.servlet.DwrServlet.init(DwrServlet.java:83)
        at weblogic.servlet.internal.ServletStubImpl$ServletInitAction.run(Servl
etStubImpl.java:1028)
        at weblogic.security.acl.internal.AuthenticatedSubject.doAs(Authenticate
dSubject.java:321)
        at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:
121)
        at weblogic.servlet.internal.ServletStubImpl.createServlet(ServletStubIm
pl.java:904)
        at weblogic.servlet.internal.ServletStubImpl.createInstances(ServletStub
Impl.java:883)
        at weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubI
mpl.java:822)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlet(WebAppS
ervletContext.java:3333)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlets(WebApp
ServletContext.java:3290)
        at weblogic.servlet.internal.WebAppServletContext.preloadServlets(WebApp
ServletContext.java:3276)
        at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAp
pServletContext.java:3259)
        at weblogic.servlet.internal.WebAppServletContext.setStarted(WebAppServl
etContext.java:5949)
        at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:862)
        at weblogic.j2ee.J2EEApplicationContainer.start(J2EEApplicationContainer
.java:2127)
        at weblogic.j2ee.J2EEApplicationContainer.activate(J2EEApplicationContai
ner.java:2168)
        at weblogic.j2ee.J2EEApplicationContainer.activate(J2EEApplicationContai
ner.java:2115)
        at weblogic.management.deploy.slave.SlaveDeployer$Application.setActivat
ion(SlaveDeployer.java:3082)
        at weblogic.management.deploy.slave.SlaveDeployer.setActivationStateForA
llApplications(SlaveDeployer.java:1751)
        at weblogic.management.deploy.slave.SlaveDeployer.resume(SlaveDeployer.j
ava:359)
        at weblogic.management.deploy.DeploymentManagerServerLifeCycleImpl.resum
e(DeploymentManagerServerLifeCycleImpl.java:229)
        at weblogic.t3.srvr.SubsystemManager.resume(SubsystemManager.java:131)
        at weblogic.t3.srvr.T3Srvr.resume(T3Srvr.java:966)
        at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:361)
        at weblogic.Server.main(Server.java:32)
Caused by: java.lang.ExceptionInInitializerError
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct
orAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC
onstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
        at java.lang.Class.newInstance0(Class.java:308)
        at java.lang.Class.newInstance(Class.java:261)
        at org.directwebremoting.impl.ContainerUtil.configureFromAnnotations(Con
tainerUtil.java:306)
        at org.directwebremoting.impl.ContainerUtil.configureContainerFully(Cont
ainerUtil.java:402)
        at org.directwebremoting.servlet.DwrServlet.init(DwrServlet.java:77)
        ... 23 more


我的dwr版本是dwr-2.0.M4.jar，Servlet使用的是org.directwebremoting.servlet.DwrServlet，系统日志是使用log4j，WEB-INF/LIB下面的jar包还有：log4j-1.2.8.jar和commons-logging.jar，请教这个可能是由于什么原因导致的？

failed to preload on startup in Web application

部署程序时选择的方式不对，

请使用复制部署的方式