symfony 1.4 showing 500 internal server error

I have setup symfony 1.4 on Amazon AMI, Linux. I've configured everything but am still getting 500 internal server error. Also I am new to symfony.

Here is my vhost entry:

<VirtualHost *:80>
    ServerName ec2-50-17-85-111.compute-1.amazonaws.com
    DocumentRoot "/var/www/html/flumenCode/web"
    DirectoryIndex index.php
    <Directory "/var/www/html/flumenCode/web">
            AllowOverride All
            Allow from All
    </Directory>
    Alias /sf /var/www/html/firstlumen/lib/vendor/symfony/data/web/sf
    <Directory "/var/www/html/firstlumen/lib/vendor/symfony/data/web/sf">
      AllowOverride All
      Allow from All
    </Directory>
</VirtualHost>

My Error Log shows:

[Fri Apr 27 08:49:11 2012] [error] [client 2.127.103.112] PHP Fatal error:  require():       Failed opening required '/var/www/html/flumenCode/cache/frontend/prod/config/config_config_handlers.yml.php' (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/flumenCode/lib/vendor/symfony/lib/config/sfConfigCache.class.php on line 279

Solution

As @bacardnumberone said, it's a cache problem. Run:

sudo ./symfony project:permissions
./symfony cc