Java EE (Java Enterprise Edition) General Discussion

I had configured following the lomboz tutorial yet,however,when I run server(tomcat v5.0 x),the console will always show me this:

Bootstrap: Class loader creation threw exception
java.lang.ExceptionInInitializerError
at org.apache.catalina.startup.ClassLoaderFactory.<clinit>(ClassLoaderFactory.java:63)
at org.apache.catalina.startup.Bootstrap.initClassLoaders(Bootstrap.java:103)
at org.apache.catalina.startup.Bootstrap.init(Bootstrap.java:196)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:402)
Caused by: org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException))
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
at org.apache.tomcat.util.compat.JdkCompat.<clinit>(JdkCompat.java:55)
... 4 more
Caused by: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException)
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:397)
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
... 8 more
Caused by: java.lang.NullPointerException
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:374)
... 9 more

if u know how to solve that,please reply to me
thanks a lot!