Ready to go live, but helpers won't load! [SOLVED]

[eluser]CoderReborn[/eluser]
I have the following line in my autoload file:

$autoload['helper'] = array('MY_model_helper', 'MY_array_helper', 'MY_string_helper', 'url', 'form', 'string', 'date', 'cookie');

This has been working fine on my Mac for months.
I believe that I have to specify the "MY_" prefix since I'm specifying that "MY_array_helper" (custom) needs to be autoloaded.
"array_helper" is already loaded by the system.

But for some reason, I'm running into a fatal error msg (in my first post), when I deployed on a hosted server.

If I remove "MY_model_helper" in the autoload file above, then I just get the following error:

"An Error Was Encountered
Unable to load the requested file: helpers/my_model_helper.php"