issue with controllers Help!!! :(

[eluser]LeonardoRaygoza[/eluser]
Hi, I'm having a problem because I created a new controller with a simple function called hello, with just a function index(), but it's appear like it doesn't run right.

my controller name is: blog
my code is:

<?php
class Blog extends Controller
{
function index()
{
echo "Hello world!";
}
}
?>

I tryied to check it on my server with my domain for example: http://www.leonardoraygoza.com/blog/

it suppouse show Hello world!

on my localhost it works! but on my web server it doesn't

I have on my config file system > application > config > config.php

$config['base_url'] = "http://localhost/"; //localhost

$config['base_url'] = "http://leonardoraygoza.com/"; //webserver

so I don't know where I'm wrong :'( can please somebody help me