Redeployment of application in Tomcat fails

Both methods of redeployment cause this error,
either by pressing reload link in Tomcat manager webapp
and by touching web.xml in load-demo webapplication.

Log excerpt:

31.08.2010 10:30:41 org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
31.08.2010 10:30:41 org.jboss.modcluster.ModClusterService
DEBUG: Stop context [/load-demo] in host [localhost]
31.08.2010 10:30:41 org.jboss.modcluster.ModClusterService
DEBUG: Start context [/load-demo] in host [localhost]
31.08.2010 10:30:41 org.apache.catalina.core.StandardPipeline registerValve
INFO: Can't register valve org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve[/load-demo]
java.lang.NoClassDefFoundError: org/jboss/servlet/http/HttpEvent
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
at java.lang.Class.privateGetPublicMethods(Class.java:2547)
at java.lang.Class.getMethods(Class.java:1410)
at org.apache.tomcat.util.modeler.modules.MbeansDescriptorsIntrospectionSource.createManagedBean(MbeansDescriptorsIntrospectionSource.java:304)
at org.apache.tomcat.util.modeler.modules.MbeansDescriptorsIntrospectionSource.execute(MbeansDescriptorsIntrospectionSource.java:84)
at org.apache.tomcat.util.modeler.modules.MbeansDescriptorsIntrospectionSource.loadDescriptors(MbeansDescriptorsIntrospectionSource.java:77)
at org.apache.tomcat.util.modeler.Registry.load(Registry.java:754)
at org.apache.tomcat.util.modeler.Registry.loadDescriptors(Registry.java:866)
at org.apache.tomcat.util.modeler.Registry.findManagedBean(Registry.java:651)
at org.apache.tomcat.util.modeler.Registry.findManagedBean(Registry.java:963)
at org.apache.tomcat.util.modeler.Registry.registerComponent(Registry.java:794)
at org.apache.catalina.core.StandardPipeline.registerValve(StandardPipeline.java:302)
at org.apache.catalina.core.StandardPipeline.addValve(StandardPipeline.java:448)
at org.jboss.modcluster.catalina.CatalinaContext.addRequestListener(CatalinaContext.java:114)
at org.jboss.modcluster.ModClusterService.start(ModClusterService.java:385)
at org.jboss.modcluster.catalina.CatalinaEventHandlerAdapter.lifecycleEvent(CatalinaEventHandlerAdapter.java:257)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4540)
at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3391)
at org.apache.catalina.manager.ManagerServlet.reload(ManagerServlet.java:943)
at org.apache.catalina.manager.HTMLManagerServlet.reload(HTMLManagerServlet.java:556)
at org.apache.catalina.manager.HTMLManagerServlet.doGet(HTMLManagerServlet.java:121)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
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.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:563)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
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:298)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:861)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1584)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException: org.jboss.servlet.http.HttpEvent
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
... 38 more

As I can see, it is caused by wrong method signature in class
org.jboss.modcluster.catalina.CatalinaContext.RequestListenerValve

public void event(Request request, Response response, HttpEvent event) throws IOException, ServletException