Mod_python error: "PythonHandler shopsys"

Traceback (most recent call last):

  File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 299, in HandlerDispatch
    result = object(req)

  File "/var/www/shopsys/shopsys.py", line 111, in handler
    return _shop.run( req = req )

  File "/home/plysak/CVS/shopsys//lib/appShop.py", line 233, in run
    log.ni("ITEMSEARCH: %s", _current_category['path'], DBG=1 )

TypeError: unsubscriptable object