apache > cocoon

Cocoon won't start, and I get a "java.lang.NoSuchMethodError: org.apache.log.LogKit: method createLogger(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/apache/log/Logger; not found" in my Servlet Container's log.

You have an old set of libraries installed. Copy the correct libraries from the distribution.

Even better, build Cocoon with "build webapp". This build creates a complete WAR file with all necessary libraries included.