Spl_autoload_register无法打开流

Question

这是Server / Init.php：

spl_autoload_register(function($file) {
    include str_replace('\\, '/', $file) . '.php';
});

$GLOBALS['config']  = $config;
$GLOBALS['patched'] = $patched;
$GLOBALS['crumbs']  = $crumbs;

$utils = new Utils();
$mysql = new MySQL();
$GLOBALS['utils'] = $utils;
$GLOBALS['mysql'] = $mysql;

问题似乎是尝试包含Utils.php，它位于classes文件夹中。这些是错误：

Warning: include(Utils.php): Failed to open stream: No such file or directory in C:/xampp/htdocs/server/Init.php on line 9

Warning: include(): Failed opening 'Utils.php' for inclusion (include_path='.;C:/xampp/php/PEAR') in C:/xampp/htdocs/server/Init.php on line 9

Fatal error: Class 'Utils' not found in C:/xampp/htdocs/server/Init.php on line 16

如果有帮助，这是Server / Classes / Utils.php：

class Utils {

    public function writeRawOutput($str) {
        echo $str;
    }

    public function writeOutput($msg, $type = null, $pref = null) {
        $msg = strval($msg);
        if($type == null && $pref == null)
            echo "$msg \r\n";
        elseif($type == null && $pref != null)
            echo "[$pref] > $msg \r\n";
        elseif($type != null && $pref == null)
            echo "[$type] > $msg \r\n";
        elseif($type != null && $pref != null)
            echo "[$pref] [$type] > $msg \r\n";
    }

    public function getInput($str) {
        $this->writeOutput($str);
        $input = trim(fgets(STDIN));
        return $input;
    }

    public function getConfig($path = null) {
        if($path) {

            $config = $GLOBALS['config'];
            $path   = explode('/', $path);

            foreach($path as $bit) {
                if(isset($config[$bit])) {
                    $config = $config[$bit];
                }
            }

            return $config;
        }
        return false;
    }

}

我做错了什么，如何解决这个问题？