software-center windows border shows but nothing else comes up

Binary package hint: software-center

When i run software-center window comes up but nothing else inside the window comes .. Initially I ran software-center from terminal and it used to print some error about dbus repeatedly..
from ~/.cache/software-center
2011-05-06 16:16:15,496 - dbus.connection - ERROR - Exception in handler for D-Bus signal:
Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.7/dbus/connection.py", line 214, in maybe_handle_message
    self._handler(*args, **kwargs)
  File "/usr/lib/pymodules/python2.7/dbus/bus.py", line 71, in signal_cb
    callback(new_owner)
  File "/usr/share/software-center/softwarecenter/backend/transactionswatcher.py", line 42, in _register_active_transactions_watch
    current, queued = apt_daemon.GetActiveTransactions()
  File "/usr/lib/pymodules/python2.7/dbus/proxies.py", line 140, in __call__
    **keywords)
  File "/usr/lib/pymodules/python2.7/dbus/connection.py", line 630, in call_blocking
    message, timeout)
DBusException: org.freedesktop.DBus.Error.NoReply: Message did not receive a reply (timeout by message bus)

 then i apt-get update and apt-get dist-upgrade .. and now if i run software-center no error comes on the term but still nothing shows in the window .. i can although close the window from menu after which it asked me to force quit it .. and one more thing I have noticed is that after I force quit software-center update-software shows up in my processes .. also aptd process start taking up cpu time ..

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: software-center 4.0
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Fri May 6 16:05:08 2011
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: software-center
UpgradeStatus: Upgraded to natty on 2011-04-29 (6 days ago)