Mod_python error: "PythonHandler trac.web.modpython_frontend"

Traceback (most recent call last):

  File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 287, in HandlerDispatch
    log=debug)

  File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 461, in import_module
    f, p, d = imp.find_module(parts[i], path)

ImportError: No module named trac