[till]

$password = crypt($_POST['password']);

Thats not crypt-md5 encryption. Crypt can create many different algorithms, see php manual. Take a look here on how to create a crypt-md5 password.

function crypt_password($cleartext_password) {
		$salt="$1$";
		$base64_alphabet='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
		for ($n=0;$n<8;$n++) {
			$salt.=$base64_alphabet[mt_rand(0,63)];
		}
		$salt.="$";
		return crypt($cleartext_password,$salt);
	}