SP5, sitemap issue on versioning tree at page field level

At page field level, versioning sub engine, the versioning tree doest not display the versions list (screenshot)
I have this exception in the console:

2008-09-09 15:26:59,453: ERROR [org.jahia.ajax.sitemap.GetChildPagesEntryPoint] - Unable to process the request !
java.lang.NullPointerException
at org.jahia.ajax.sitemap.SiteMapAbstractAction.processPage(SiteMapAbstractAction.java:420)
at org.jahia.ajax.sitemap.GetChildPagesEntryPoint.execute(GetChildPagesEntryPoint.java:122)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
at org.jahia.bin.JahiaRequestProcessor.process(JahiaRequestProcessor.java:82)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.jahia.bin.filters.esi.ESIFilter.doFilter(ESIFilter.java:110)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:595)
2008-09-09 15:27:01,703: INFO [org.jahia.views.engines.versioning.actions.ContentVersioningAction] - Logged in User :root
2008-09-09 15:27:01,734: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/PagesVersioning] user=[root] ip=[127.0.0.1] in [31ms]
2008-09-09 15:27:06,109: INFO [org.jahia.views.engines.versioning.actions.ContentVersioningAction] - Logged in User :root
2008-09-09 15:27:06,140: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/PagesVersioning] user=[root] ip=[127.0.0.1] in [31ms]
2008-09-09 15:27:17,562: INFO [org.jahia.views.engines.versioning.actions.ContentVersioningAction] - Logged in User :root
2008-09-09 15:27:17,578: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/PagesVersioning] user=[root] ip=[127.0.0.1] in [16ms]
[GC 405910K->310225K(1032512K), 0.5078246 secs]
2008-09-09 15:29:24,593: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/engineName/pageproperties/site/demo/op/edit/home/about_us/pid/58] user=[root] ip=[127.0.0.1] in [15ms]
2008-09-09 15:29:26,406: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/engineName/pageproperties/site/demo/op/edit/home/about_us/pid/58] user=[root] ip=[127.0.0.1] in [31ms]
2008-09-09 15:29:27,328: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/engineName/pageproperties/site/demo/op/edit/home/about_us/pid/58] user=[root] ip=[127.0.0.1] in [16ms]
2008-09-09 15:29:27,359: INFO [org.jahia.views.engines.versioning.actions.ContentVersioningAction] - Logged in User :root
2008-09-09 15:29:27,359: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/PagesVersioning] user=[root] ip=[127.0.0.1] in [0ms]
2008-09-09 15:29:28,734: INFO [org.jahia.views.engines.versioning.actions.ContentVersioningAction] - Logged in User :root
2008-09-09 15:29:28,734: INFO [org.jahia.bin.Jahia] - Processed [/jahia/Jahia/PagesVersioning] user=[root] ip=[127.0.0.1] in [0ms]
2008-09-09 15:29:29,750: ERROR [org.jahia.ajax.sitemap.GetChildPagesEntryPoint] - Unable to process the request !
java.lang.NullPointerException
at org.jahia.ajax.sitemap.SiteMapAbstractAction.processPage(SiteMapAbstractAction.java:420)
at org.jahia.ajax.sitemap.GetChildPagesEntryPoint.execute(GetChildPagesEntryPoint.java:122)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
at org.jahia.bin.JahiaRequestProcessor.process(JahiaRequestProcessor.java:82)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.jahia.bin.filters.esi.ESIFilter.doFilter(ESIFilter.java:110)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:595)