Why doesn't anything happen when I access 'http://localhost/cocoon/'?

You might want to check a few things.

• Is your server listening to port 80? If not, you have to call the right port, for example, 'http://localhost:8080/cocoon/'. Note that Apache Tomcat binds by default to port 8080, NOT 80.
• Did your servlet engine install the WAR file? You can check this by making sure the WAR file was unpacked or connecting to the administration tools of your servlet engine.
• If you didn't restart the servlet engine, do it.
• In Tomcat 4, did you change CATALINA_BASE to a different value than the default CATALINA_HOME? If so, copy the war files to CATALINA_BASE/webapps or set CATALINA_BASE=CATALINA_HOME. Then, restart Tomcat.