Java EE (Java Enterprise Edition) General Discussion

I install Tomcat5.5.12 using file "apache-tomcat-5.5.12.zip",then I start Tomcat using this file apache-tomcat-5.5.12\bin\startup.bat,It show information follows:
2005-10-13 19:18:46 org.apache.commons.logging.impl.Jdk14Logger info
Info: The Apache Portable Runtime which allows optimal performance in production environments was not found on the java.library.path: c:\jdk1.5.0_04\bin;C:\WINNT;
2005-10-13 19:18:47 org.apache.commons.logging.impl.Jdk14Logger info
Info: Initializing Coyote HTTP/1.1 on http-8080
2005-10-13 19:18:47 org.apache.commons.logging.impl.Jdk14Logger info
Info: Initialization processed in 2969 ms
2005-10-13 19:18:48 org.apache.commons.logging.impl.Jdk14Logger info
info: Starting service Catalina

Then I open IE,and input http://localhost:8080,

But IE6 raise follows error:

Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Error allocating a servlet instance
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:868)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:663)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
java.lang.Thread.run(Thread.java:595)
root cause
java.lang.NoClassDefFoundError: org/apache/jasper/runtime/JspSourceDependent
java.lang.ClassLoader.defineClass1(Native Method)
java.lang.ClassLoader.defineClass(ClassLoader.java:620)
java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
java.net.URLClassLoader.access$100(URLClassLoader.java:56)
java.net.URLClassLoader$1.run(URLClassLoader.java:195)
java.security.AccessController.doPrivileged(Native Method)
java.net.URLClassLoader.findClass(URLClassLoader.java:188)
java.lang.ClassLoader.loadClass(ClassLoader.java:306)
java.lang.ClassLoader.loadClass(ClassLoader.java:299)
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
java.lang.ClassLoader.loadClass(ClassLoader.java:251)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1253)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1187)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:868)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:663)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
java.lang.Thread.run(Thread.java:595)

Why? How to configure my Tomcat5.5.12? Please help me!

Thanks in advance