That's assuming server runs PHP as apache's module (you might not even run on apache!), otherwise it will not work.
You'll have to use ini_set() function inside a .php file instead, for example, by placing ini_set('memory_limit', '256M'); in oc_load.php.
And all above will work only if overrides are allowed by PHP's main config (e.g. in main php.ini). On some servers it is disabled for security or because host does not allow changes.