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 "/var/lib/python-support/python2.4/trac/web/modpython_frontend.py", line 87, in handler
    gateway.run(dispatch_request)

  File "/var/lib/python-support/python2.4/trac/web/wsgi.py", line 87, in run
    response = application(self.environ, self._start_response)

  File "/var/lib/python-support/python2.4/trac/web/main.py", line 420, in dispatch_request
    req.send_error(sys.exc_info(), status=500)

  File "/var/lib/python-support/python2.4/trac/web/api.py", line 380, in send_error
    data = self.hdf.render(template)

  File "/var/lib/python-support/python2.4/trac/web/clearsilver.py", line 290, in render
    template.parseFile(filename)

ParseError: ParseError: [/var/www/plumi/templates/site_css.cs:1] Missing end ?> at ##################################################################
# Site CSS - Place custom CSS, including overriding styles here.
# added by lachlan 10/07/2007 for tracnav implementation

@impor