Error shown and unable to start Software Center

Hello experts

I cannot start Software Center. Please help me to solve this. When I attempt to start with terminal, it gives me the following error.

developer@shantanu-desktop:~$ software-center

2011-10-22 18:51:29,178 – softwarecenter.ui.gtk3.em – INFO – EM's: 17 15 21

2011-10-22 18:51:54,355 – softwarecenter.fixme – WARNING – logs to the root logger: '('/usr/lib/python2.7/dist-packages/dbus/proxies.py', 406, '_introspect_error_handler')'

2011-10-22 18:51:54,354 – dbus.proxies – ERROR – Introspect error on :1.120:/com/ubuntu/Softwarecenter: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

2011-10-22 18:52:20,000 – softwarecenter.backend.reviews – WARNING – Could not get usefulness from server, no username in config file

2011-10-22 18:52:20,110 – softwarecenter.ui.gtk3.utils – INFO – Softwarecenter style provider for ambience Gtk theme: /usr/share/software-center/ui/gtk3/css/softwarecenter.css

Also, I cannot look for any apps in dash. When I tried to search, only recent files are displayed. There are no apps in any other option, but all the apps are working fine. It occurs after reboot.

Please help.

Thanks a lot.