Codeigniter vhost LAMP configuration troubleshoot - php

Question

Running LAMP on UBUNTU 14LTS on virtualbox from win7 I found some hiccups.
I'm having trouble displaying my code igniter project in my machine. I have a followed some guides including this one:
tut 1 and tut 2
I can make the current configuration show a single HTML page, called example.com but it cannot show a complete code igniter project, I get this error when running it through the localhost:
NOT FOUND The requested URL /alpa_blog/en was not found on this server.
The project I'm working on is very big so bitnami is a bitslow so I'm planning to change to LAMP that is why I wanted to try and see a little blog on my localhost.
I have not used the LAMP on apache 2.4+ so I'm a little confuse about how to edit some files on vhost and tie them to the config.php inside code igniter.
I've tried a lot of different combination things but no success yet. Now I have my files #:
/etc/apache2/sites-available/alpa_blog.com.conf
/etc/apache2/sites-enabled/alpa_blog.com.conf
Looking like:
<VirtualHost *:80>
ServerName alpa_blog.com
ServerAlias www.alpa_blog.com
DocumentRoot /var/www/html/alpa_blog.com/application
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
And # /etc/apache2/sites-available/000-default.conf
looks like:
<VirtualHost *:80>
ServerAdmin webmaster#localhost
DocumentRoot /var/www/html/
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
<Directory /var/www/html>
Options Indexes FollowSymLinks MultiViews
AllowOverride All
</Directory>
Plus my file alpa_blog.com/config/config.php code igniter's folder looks like:
$config['base_url'] = 'alpa_blog.com';
My etc/hosts folder looks like:
127.0.0.1 localhost
127.0.1.1 alpalamp-VirtualBox
127.0.1.1 example.com localhost
127.0.1.1 alpa_blog.com localhost
My var/www/html folder looks like:
alpa_blog.com ci example.com index.html phpinfo.php
Any pointers are much appreciated. Sorry for the your supposed to know that question, but it's driving me nuts.
EDIT:
I've tried several configurations on the .htaccess file.
This is my last version of the .htaccess:
RewriteEngine On
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ http%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
And config.php is like:
$config['index_page'] = '';

Answer 1

So after a while I found the answer, I thought to post it here just in case.
Going in the log file located at var/log/apache2/error.log I found this message:
[core:alert] [...] /var/www/html/APP-NAME/www/.htaccess: RewriteRule: bad flag delimiters, turns out that a regex expression was not properly written.
I Ended up by rewriting the rule on the .htaccessfile like this:
RewriteEngine on
RewriteCond $1 !^(index\.php|images|assets|uploads|robots\.txt)
RewriteRule ^(.*)$ /index.php/ [L]
Which solved the issue.
This post also helped out