NPE in ConfluenceWebWorkConfiguration under OC4J

This is an error that appears in the logs:

05/03/14 17:53:08 atlassian-confluence: Error initializing servlet
java.lang.NullPointerException
at com.atlassian.confluence.setup.webwork.ConfluenceWebWorkConfiguration.getImpl(ConfluenceWebWorkConfiguration.java:58)
at com.opensymphony.webwork.config.DelegatingConfiguration.getImpl(DelegatingConfiguration.java:81)
at com.opensymphony.webwork.config.Configuration.get(Configuration.java:139)
at com.opensymphony.webwork.config.Configuration.getString(Configuration.java:125)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.init(ServletDispatcher.java:166)
at com.evermind.server.http.HttpApplication.loadServlet(HttpApplication.java:2094)