Mod_python error: "PythonHandler invenio.webinterface_layout"

Traceback (most recent call last):

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

  File "/usr/lib/python2.4/site-packages/invenio/webinterface_handler.py", line 298, in _profiler
    return _handler(req)

  File "/usr/lib/python2.4/site-packages/invenio/webinterface_handler.py", line 332, in _handler
    register_exception(req=req, alert_admin=True)

  File "/usr/lib/python2.4/site-packages/invenio/errorlib.py", line 229, in register_exception
    print >> sys.stderr, "Error in registering exception to '%s': '%s'" % (CFG_LOGDIR + '/invenio.' + stream, e)

IOError: [Errno 30] Read-only file system