I just setup openstack, when I first time open the dashboard, there was an error:

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, root@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Apache/2.2.15 (CentOS) Server at 192.168.20.229 Port 80

also I find some log in /var/log/httpd/error_log:

[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3] mod_wsgi (pid=3301): Exception occurred processing WSGI script '/usr/share/openstack-dashboard/openstack_dashboard/wsgi/django.wsgi'.
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3] Traceback (most recent call last):
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/lib/python2.6/site-packages/django/core/handlers/wsgi.py", line 219, in __call__
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     self.load_middleware()
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/lib/python2.6/site-packages/django/core/handlers/base.py", line 39, in load_middleware
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     for middleware_path in settings.MIDDLEWARE_CLASSES:
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/lib/python2.6/site-packages/django/utils/functional.py", line 184, in inner
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     self._setup()
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/lib/python2.6/site-packages/django/conf/__init__.py", line 42, in _setup
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     self._wrapped = Settings(settings_module)
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/lib/python2.6/site-packages/django/conf/__init__.py", line 93, in __init__
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     mod = importlib.import_module(self.SETTINGS_MODULE)
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/lib/python2.6/site-packages/django/utils/importlib.py", line 35, in import_module
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     __import__(name)
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/settings.py", line 221, in <module>
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]     from local.local_settings import *  # noqa
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]   File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/local/local_settings.py", line 98
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1.3]      CACHES = {
[Thu Mar 27 20:15:17 2014] [error] [client 172.16.1 ...