There is no Action mapped for namespace /conf/pages and action name diffpages

From the c.a.c logs

2005-10-21 03:27:08,604 ERROR [opensymphony.webwork.dispatcher.ServletDispatcher] Could not find action
com.opensymphony.xwork.config.ConfigurationException: There is no Action mapped for namespace /labels and action name autocompletelabelslist
at com.opensymphony.xwork.DefaultActionProxy.<init>(DefaultActionProxy.java:72)
at com.opensymphony.xwork.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:45)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.serviceAction(ServletDispatcher.java:227)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:199)