[CentOS-mirror] directory index forbidden by rule, when i setup the apache access site

[Kelphon]

Dear all
	I have setup a sync with mirror.centos.org at shanghai in china. 
	Then I setup the apache with the following configuration
<VirtualHost *:80>
ServerName mirror.kingstor.com
ServerAlias mirrors.kingstor.com
DocumentRoot "/var/ftp/mirror"
Options Indexes FollowSymLinks MultiViews
<Directory "/var/ftp/mirror/">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride None
    Order allow,deny
    Allow from all
</Directory>
#SuexecUserGroup mirror mirror
</VirtualHost>

And I encounter the problem:
When I browser http://mirror.kingstor.com/ I get 404 error
When I browser http://mirror.kingstor.com/centos/ I get the centos mirror's
directory list.

When is check the error_log file I found the following error message 
[Sun Feb 04 17:08:51 2007] [error] [client 218.1.223.70] Directory index
forbidden by rule: /var/ftp/mirror/
[Sun Feb 04 17:08:51 2007] [error] [client 218.1.223.70] File does not
exist: /var/ftp/mirror/error
[Sun Feb 04 17:08:56 2007] [error] [client 218.1.223.70] File does not
exist: /var/ftp/mirror/favicon.ico

** Directory index forbidden by rule, ** 

How to fix this error ? Thank you in advance.;)