Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/view/channelpane.py", line 123, in on_search_terms_changed
    self.refresh_apps()
  File "/usr/share/software-center/softwarecenter/view/softwarepane.py", line 56, in wrapper
    f(*args, **kwargs)
  File "/usr/share/software-center/softwarecenter/view/channelpane.py", line 98, in refresh_apps
    xapian.Query("ATapplication"))
  File "/usr/lib/python2.6/dist-packages/xapian.py", line 3396, in __init__
    _xapian.Query_swiginit(self,_xapian.new_Query(*args))
TypeError: in method 'new_Query', argument 1 of type 'std::string const &'