Mod_python error: "PythonHandler mod_python.publisher"

Traceback (most recent call last):

  File "/usr/lib/python2.3/site-packages/mod_python/apache.py", line 299, in HandlerDispatch
    result = object(req)

  File "/usr/lib/python2.3/site-packages/mod_python/publisher.py", line 136, in handler
    result = util.apply_fs_data(object, req.form, req=req)

  File "/usr/lib/python2.3/site-packages/mod_python/util.py", line 361, in apply_fs_data
    return object(**args)

  File "/var/www/html/www.modpython.org/examples/psp_site/index.py", line 49, in index
    return home(req)

  File "/var/www/html/www.modpython.org/examples/psp_site/index.py", line 52, in home
    return _any_page(req, 'home')

  File "/var/www/html/www.modpython.org/examples/psp_site/index.py", line 121, in _any_page
    vars = {"menu": _menu(req, hlight=name),

  File "/var/www/html/www.modpython.org/examples/psp_site/index.py", line 109, in _menu
    m = psp.PSP(req, tmpl, vars={'hlight':hlight})

AttributeError: 'module' object has no attribute 'PSP'