java.lang.NullPointerException

[cardio palma]

Dear everybody,

I'm facing the following issue:

When I access jenkins login page (logged out), and when I logout too (same page), I get the following error:

java.lang.NullPointerException
 at java.util.TreeMap.put(TreeMap.java:556)
 at java.util.TreeSet.add(TreeSet.java:255)
 at jenkins.model.Jenkins.getUnprotectedRootActions(Jenkins.java:3876)
 at jenkins.model.Jenkins.getTarget(Jenkins.java:3852)
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:674)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
 at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132)
 at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:123)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:49)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
 at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:135)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
 at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
 at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:558)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
 at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
 at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
 at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:769)
 at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:698)
 at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:891)
 at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
 at java.lang.Thread.run(Thread.java:745)

Looking around the web to see if somebody else encountered similar problems,
I found this post : https://issues.jenkins-ci.org/browse/JENKINS-24336
But they are talking about an "old" version 1.576, the issue should be resolved in the current version I've installed Jenkins ver. 1.625.3
I've also tried to install the latest one: 1.653

Does anybody have some hint for me?
Many thanks for any kind of help