403 forbidden while accessing a page using apache2

Hi All,
i am trying to Access a siremis page using apache2 i am getting 403 forbidden. below is config for siremis in httpd.conf

Code:

Alias /siremis "/opt/siremis-4.0.0/siremis"
        <Directory "/opt/siremis-4.0.0/siremis">
                Options Indexes FollowSymLinks MultiViews
                AllowOverride All
               #AllowOverride none
                Order deny,allow
                Allow from all
                <FilesMatch "\.xml$">
                        Order deny,allow
                        Allow from all
                </FilesMatch>
                <FilesMatch "\.inc$">
                        Order deny,allow
                       Allow from all
                </FilesMatch>
        </Directory>

when i change

Code:

AllowOverride none 

i was able to access the page but i am getting below error when try to login

Code:

404
The requested URL /siremis/system/general_default was not found on this server.

mod_rewrite is available apache2
i have set chmod 777 for entire folder

Please let me know how to resolve this .

Thanks 'n' Regards,
Prem