While I am trying to Reboot or Shutdown my system using the menu, I am again routed to Login page. From the login page I am not able to shutdown or reboot the system, only thing i can do is to login.
Freevo was the trouble maker. I uninstall Freevo and shutdown works fine.
Occasionally, i press CTRL+ALT+F9 and found Freevo, it was starting automatically on boot. I press exit and Freevo closed. After this i go to previos default tty (CTRL+ALT+F7), and then shutdown Ubuntu successfully. This i have found in logs:
I think that i was unable to shutdown, because of another user "freevo", which was logged in automatically on boot.