Software Center has blank screen

[Samop]

When initially running Software Center all is OK but after I close it, when rerunning it come up with a blank screen.

This all started when I upgraded to 12.04. It was OK with 11.10

I have done a complete removal, reboot and install form the package manager but that made no difference.

If I type "killall software-center" in a terminal it will then run OK but once again, after closing it will fail the next run.

If run from the terminal, after closing these errors are reported...

IOError: [Errno 5] Input/output error: '/home/sam/.config/software-center/softwarecenter.cfg.new'
2012-05-01 09:16:43,148 - softwarecenter.ui.gtk3.app - INFO - software-center-agent finished with status 0
2012-05-01 09:16:43,150 - softwarecenter.db.database - INFO - reopen() database
2012-05-01 09:16:43,150 - softwarecenter.db.database - INFO - open() database: path=None use_axi=True use_agent=True
Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/availablepane.py", line 577, in on_db_reopen
    self.refresh_apps()
  File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/availablepane.py", line 788, in refresh_apps
    SoftwarePane.refresh_apps(self, query)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/softwarepane.py", line 432, in refresh_apps
    self._refresh_apps_with_apt_cache(query)
  File "/usr/share/software-center/softwarecenter/utils.py", line 118, in wrapper
    f(*args, **kwargs)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/softwarepane.py", line 451, in _refresh_apps_with_apt_cache
    self.app_view.configure_sort_method(self._is_in_search_mode())
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/appview.py", line 223, in configure_sort_method
    self._use_combobox_without_sort_by_search_ranking()
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/appview.py", line 155, in _use_combobox_without_sort_by_search_ranking
    if self._get_combo_children() == 3:
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/appview.py", line 147, in _get_combo_children
    return len(self.sort_methods_combobox.get_model())
TypeError: object of type 'NoneType' has no len()

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: software-center 5.2
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic-pae 3.2.14
Uname: Linux 3.2.0-24-generic-pae i686
NonfreeKernelModules: wl
ApportVersion: 2.0.1-0ubuntu7
Architecture: i386
Date: Tue May 1 09:11:47 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: software-center
UpgradeStatus: Upgraded to precise on 2012-04-27 (3 days ago)

[Gary Lasker (gary-lasker)]

Hello Sam! Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 885726, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.

Many thanks for your help!