Linux-shared host : Requested Url not found when Zend index controller is lowercase

Question

I'm testing a Zend project on my shared-hosting with Linux server.I keep everything inside a folder 'Zend-project' not on the server public-root (cause I have there another project!).

Problem: whenever I type:

mysite.com/zend-project/index/index 

I receive the following message:

Not Found.
The requested URL /zend-project/index/index was not found on this server.

It looks like that it is not reaching index.php so I thought the problem is in the .htaccess file.The point is that it works if I type the controller name with first-letter capitalized:

mysite.com/zend-project/Index/index

edit:I tried creating a new controller 'TestController'..with a single action (called 'test')I tried to type the url with the controller lowercase (mysite.com/zend-project/test/test)and it's working!As I suspected there should be something wrong with the 'index' word itself!

Even if I type a wrong controller name (mysite.com/zend-project/qwerty/index) I can get the front controller to run with an exception generated : Invalid controller specified (qwerty)

this is the project's structure:

/public_root
  /zend-project
    /application
      /configs
        application.ini
      /controllers
        IndexController.php
      /layouts
      /views
      bootstrap.php
    /css
    /images
    /javascript
    /zend-library
    .htaccess
    index.php

I had to tweak a little the project cause I just can't change my document_root on a shared-hosting so I edited the .htaccess to this:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} -s [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d 
RewriteRule ^.*$ - [NC,L]
RewriteRule ^.*$ /zend-project/index.php [NC,L]

This is my index.php

//IDENTIFY THE LOCATION OF THE APPLICATION DIRECTORY IN RESPECT TO 
//THE BOOTSTRAP FILE'S LOCATION,AND CONFIGURE PHP'S INCLUDE_PATH TO
//INCLUDE THE LIBRARY DIRECTORY'S LOCATION

echo"we are inside index.php";
define('APPLICATION_PATH',realpath(dirname(__FILE__).'/application/'));
set_include_path(APPLICATION_PATH.'/../Zend-library'.PATH_SEPARATOR.get_include_path());


/** Zend_Application */
require_once APPLICATION_PATH.'/../Zend-library/Zend/Application.php';

// Define application environment
defined('APPLICATION_ENV')|| define('APPLICATION_ENV',(getenv('APPLICATION_ENV') ? getenv('APPLICATION_ENV'): 'development')); 

// Create application, bootstrap, and run
$application = new Zend_Application(
APPLICATION_ENV,
APPLICATION_PATH . '/configs/application.ini'
);
$application->bootstrap()
            ->run();

This is my bootstrap.php

class Bootstrap extends Zend_Application_Bootstrap_Bootstrap
{

protected function _initRoutes()
{

$frontController=Zend_Controller_Front::getInstance();
$router=$frontController->getRouter();  
$router->removeDefaultRoutes();
$router->setGlobalParam('lang','en');
$router->addRoute(
        'lang',
        new Zend_Controller_Router_Route(':lang/:controller/:action',
        array('lang'=>':lang',
        'module'=>'default',
        'controller'=>'index',
        'action'=>'index'

        )

        )
);


        //the following route is not working remotely.
        //Is working on local environment
$router->addRoute(
'langController',
new Zend_Controller_Router_Route(':controller/:action',
array(

        'module'=>'default',
        'controller'=>'index',
        'action'=>'index'
        )

)
);

        $router->addRoute(
'langIndex',
new Zend_Controller_Router_Route(':lang',
array('lang'=>':lang',
        'module'=>'default',
        'controller'=>'index',
        'action'=>'index'
        )

 )
);

        $router->addRoute(
'langNothing',
new Zend_Controller_Router_Route('',
array(
        'module'=>'default',
        'controller'=>'index',
        'action'=>'index'
        )

)
);

 }
}

where is the problem??

thanks

Luca