I launch it and it goes grey for almost immediately. Closing it prompts me to "force close" and no error report is given.
I launched it in Terminal and this was the resulting log:
2012-11-23 22:39:25,175 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None' 2012-11-23 22:39:25,179 - softwarecenter.db.database - INFO - open() database: path=None use_axi=True use_agent=True
2012-11-23 22:39:25,409 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file
2012-11-23 22:39:25,412 - softwarecenter.fixme - WARNING - logs to the root logger: '('/usr/lib/python2.7/dist-packages/gi/importer.py', 51, 'find_module')'
2012-11-23 22:39:25,412 - root - ERROR - Could not find any typelib for LaunchpadIntegration
2012-11-23 22:39:25,474 - softwarecenter.ui.gtk3.app - INFO - show_available_packages: search_text is '', app is None