Shoutbox

well its for a tutorial section. each tutorial is a txt file in a far far away folder.
first someone will will choose a language, and then they select a page/tutorial.

i have this so far
[code]
<?php
$page = htmlentities($_GET['page']) ;
$language = htmlentities($_GET['lan']) ;
if (!isset($_GET['page'])) {
if(!isset($_GET['lan'])) {
include ("pages/code/home.txt");
}
else {
include ("pages/code/$language.txt");
}
}
else {
include("pages/code/$language/$page.txt");
}
?>

---

now i want to create a sorta error page, if the file cannot be found, then it echos "page cannot be found"

thanks for the help