404 on Live Server

First, let me apologize for what must be a common question.  I couldn't find anything that directly addressed my problem.

My code works find on my local machine.  Locally, my directory structure is as follows (some extraneous files/folders not shown):

Code:

- (server)
 - [website]
   - application
     - (CodeIgniter material: models, views, controllers, etc.)
   - css
     - (CSS files here)
   - js
     - (JavaScript files here)
   - system
     - (CodeIgniter System material)
   - .htaccess

I've moved this to my online server.  Let's say it's located at mydomain.com.  I have replicated the above structure.  At public_html/mydomain, all contents of [website] from above are present.

I've made changes to two files as part of the deployment:  application/config/config.php and application/config/database.php.  Here are the changes I made to each:

Code:

// Old line from application/config/config.php

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


// New line from application/config/config.php

$config['base_url'] = 'http://mydomain.com/';

Code:

// Old application/config/database.php

$db['default'] = array(
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => '[local database name]',
    [other parameters unchanged and not shown here]
);


// New application/config/database.php

$db['default'] = array(
    'hostname' => '[server IP]',
    'username' => '[server database username]',
    'password' => '[server database password]',
    'database' => '[server database name]',
    [other parameters unchanged and not shown here]
);

I am using mod_rewrite to remove index.php from the URL.  Here is the entirety of my .htaccess file located at the root level of my website:

Code:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
</IfModule>

Again, this all works locally.  If I go to http://localhost/mydomain, everything works as intended.  However, when I go to http://mydomain.com, I get a 404 error.  If I dive in and try to grab a JavaScript file, for example http://mydomain.com/js/helper.js, I get the file I asked for.  So something is amiss in the CodeIgniter settings.

Any help is much appreciated.  I'm happy to provide more information upon request!