Database core/Loader.php error.

[eluser]Unknown[/eluser]
I am getting an database error.

Unable to connect to your database server using the provided settings.
Filename: core/Loader.php
Line Number: 232


I have changed my config/database.php.But yet i am getting an error.It was working fine in web server but not working on Amazon EC2.

Code:

$db['default']['hostname'] = 'ec2-175-41-173-192.ap-southeast-1.compute.amazonaws.com';
$db['default']['username'] = 'root';
$db['default']['password'] = 'password';
$db['default']['database'] = 'database_name';
$db['default']['dbdriver'] = 'mysql';