无法使用路由系统显示php错误

Question

I've implemented a simple routing system in my site and now I can't see any php errors. I've spent too much time trying to debug all my files after I've uploaded them into the server.

My routing system is like this:

$slots = array(2,3,4,5,6);

$param = explode("/", stripslashes($_SERVER['REQUEST_URI']));
define('LANG',      isset($param[$slots[0]])?$param[$slots[0]]:''); $const_lang = LANG;
define('PAGE',      isset($param[$slots[1]])?$param[$slots[1]]:''); $const_page = PAGE;
define('MENU',      isset($param[$slots[2]])&&is_numeric($param[$slots[2]])?$param[$slots[2]]:0); $const_menu = MENU;
define('SUBMENU',   isset($param[$slots[3]])&&is_numeric($param[$slots[3]])?$param[$slots[3]]:0); $const_submenu = SUBMENU;
define('ID',        isset($param[$slots[4]])&&is_numeric($param[$slots[4]])?$param[$slots[4]]:0); $const_id = ID;

// LOAD PAGE
if(LANG != '' && elem_exists(LANG, $active_lang)){
    if(file_exists(PAGE.'.php') && is_readable(PAGE.'.php') && include(PAGE.'.php')){
        //include $page.'.php';
    }else{
        include 'home.php';
    }

}else{
    header("location:".BASE_URL."pt/"); 
}

I've tried changing my .htaccess file like this:

php_flag display_startup_errors on
php_flag display_errors on
php_flag html_errors on
php_flag  log_errors on
php_value error_log  /.../PHP_errors.log

I've tried changing the file php.ini directly:

; display_errors
;   Default Value: On
;   Development Value: On
;   Production Value: On

; display_startup_errors
;   Default Value: Off
;   Development Value: On
;   Production Value: On

I've tried installing libraries to get php errors like PHP Error.

I've set up error_reporting(E_ALL); at the top of my files.

And after all that when I have a php error on a page, the page comes blank without a single line of code.