Попробуй так
<?

$hash=core::Gen_Hash($login);

$mysqli->query(\'INSERT INTO `user` SET `nick` = \"\'.core::check($login).\'\", `password` = \"\'.$reg_password.\'\", `reg_time` = \"\'.time().\'\", `hash` = \"\'.$hash.\'\"\');

setcookie(\"login\", $login, time()+86400*365, \'/\');

setcookie(\"hash\", $hash, time()+86400*365, \'/\');

?>