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 299, in HandlerDispatch
    result = object(req)

  File "/usr/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/modpython_frontend.py", line 127, in handler
    from trac.web.main import dispatch_request

  File "/usr/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/main.py", line 33, in ?
    from genshi.template import TemplateLoader

  File "/usr/lib/python2.4/site-packages/Genshi-0.5-py2.4-linux-i686.egg/genshi/template/__init__.py", line 20, in ?
    from genshi.template.markup import MarkupTemplate

  File "/usr/lib/python2.4/site-packages/Genshi-0.5-py2.4-linux-i686.egg/genshi/template/markup.py", line 24, in ?
    from genshi.template.eval import Suite

  File "/usr/lib/python2.4/site-packages/Genshi-0.5-py2.4-linux-i686.egg/genshi/template/eval.py", line 17, in ?
    from compiler import ast, parse

  File "/usr/lib/python2.4/compiler/__init__.py", line 24, in ?
    from transformer import parse, parseFile

  File "/usr/lib/python2.4/compiler/transformer.py", line 28, in ?
    from compiler.ast import *

  File "/usr/lib/python2.4/compiler/ast.py", line 5, in ?
    from consts import CO_VARARGS, CO_VARKEYWORDS

ImportError: No module named consts