yaml_parse() error

I'm getting an error about yaml_parse().

Spoiler: Code

PHP:

public function resetBlockFromCFG($cf)
    {
        if($cf !== null) {
            $cfg = $this->getConfig()->get($cf);
            foreach ($cfg as $c) {
                list($world, $x, $y, $z, $blockId, $meta) = explode(":", $c);
                return $this->getServer()->getLevelByName($world)->setBlock(new Vector3($x, $y, $z), Block::get($blockId, $meta));
            }

Spoiler: error

RuntimeException: "yaml_parse(): end of stream reached without finding document 0" (E_WARNING) in "/src/pocketmine/utils/Config" at line 143

haven't you created a file next to src called recourses and in it created config.yml ?