Petit exercice de programmation html/php

<?php
$file = 'FICHIER.users';
$users = array();
$handle = fopen($file, 'r');
while ($buffer = fgets($handle)) {
	$user_data = explode(':', $buffer);
	$user_name = $user_data[0];
	$user_score = $user_data[10];
	$users[$user_name] = $user_score;
}
fclose($handle);
arsort($users, SORT_NUMERIC);
$rank = 1;
foreach ($users as $name=>$score) {
	echo "$rank - $name - $score<br />\n";
	$rank++;
}
?>

<?php

$folder = 'folder';

$files = scandir($folder);

$sort = array();

foreach($files as $file) {
	if(preg_match('/\.txt/', $file)) {
		$handle = fopen($folder.'/'.$file, 'r');
		while (!feof($handle)) {
			$line = fgets($handle);
			$sort[intval($line)] = trim($file, '.txt');
		}
	}
}

ksort($sort);
foreach($sort as $key=>$value) {
	echo $value.'-'.$key.'<br>';
}

<?php

$folder = 'folder';

$files = scandir($folder);

$sort = array();

foreach($files as $file) {
	if(preg_match('/\.txt/', $file)) {
		$handle = fopen($folder.'/'.$file, 'r');
		while (!feof($handle)) {
			$line = fgets($handle);
			if($line)
				$sort[] = array(trim($file, '.txt'), intval($line));
		}
	}
}

usort($sort, 'sort_value');
foreach($sort as $array) {
	echo $array[0].'-'.$array[1].'<br>';
}

function sort_value($a, $b) {
	if($a[1] == $b[1])
		return 0;
	return ($a[1] < $b[1]) ? -1 : 1;
}

Warning: scandir(folder): failed to open dir: No such file or directory in stats.php on line 5

Warning: scandir(): (errno 2): No such file or directory in stats.php on line 5

Warning: Invalid argument supplied for foreach() in stats.php on line 9