changing index.php's name

[eluser]idofr[/eluser]
hey everyone, i know it's a bit of a silly question for this should be rather simple but i can't get it to work.
i've changed the

Code:

$config['index_page'] = '';

line to the desired name and of course changed the name of the actual file but all i'm getting is a

HTTP Error 403.14 - Forbidden.

thnx for the help and time.