feldon, just because he's a newb doesn't mean you can post an answer without explaining.
ATLien, you're using index.php, which to PHP is two constants (index and php) that are being concatenated (appended) with the . operator. the value of an undefined constant is its name, so it's redirecting you to indexphp (as it should).
feldon's solution is the obvious one
btw, please STFW before you post 😉
hth
moon