Por k sale esto en la pagin (ITEM SHOP )

BrokerJoker

Bueno a meti MD a un pj mio (SOY ADM ) pagina de caes ....
y cuadno kero comprar lo k he metido en item shop pone esto

Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in C:\xampp\htdocs\scripts\itemshop\shopbuy.php on line 31
Kaufen fehlgeschlagen.

Aki ta la linia 31 >>>> session_start();
if($_SESSION['id'] == "") {
die('Logge dich bitte ein!');
}
else {

include('../../inc/dbsettings.php');
$db = "account";
mysql_connect($dbhost, $dbuser, $dbpw) OR
die("ERROR: Connection failed. ".mysql_error());
mysql_select_db($db) OR
die("ERROR: DB allready open. ".mysql_error());

$getuser = "SELECT * from account where login = '" . $_SESSION['id'] . "'";
$checkuser = mysql_query($getuser);
$num = mysql_num_rows($checkuser);

if($num > 0) {

$array = mysql_fetch_array($checkuser);

$itemid = $_GET['id'];
$user = $_SESSION['id'];
$coins = $_SESSION['coins'];

$check = "SELECT * from itemshop where value = '" . $itemid . "'";
$query = mysql_query($check);
$num = mysql_num_rows($query);
if($num > 0) {
$array2 = mysql_fetch_array($query);
$rescash = $array['coins'] - $array2['coins'];

if($num > 0 && $rescash >= 0) {
mysql_select_db('player');
$i = 0;
$giveitem = "INSERT INTO item SET owner_id = '" . $array['id'] . "', window = 'MALL', pos = '" . $_SESSION['pos'] . "', count = '1', vnum = '" . $itemid . "', socket0 = '0', socket1 = '0', socket2 = '0'";
$result = mysql_query($giveitem);

if($result) {

if($_SESSION['pos'] == '42') {

$_SESSION['pos'] = '0'; }
else { $_SESSION['pos'] = $_SESSION['pos'] + 1; }

mysql_select_db('account');

$cashresult = $array['coins'] - $array2['coins'];

$coins = "UPDATE account set coins = '" . $cashresult . "' where login = '" . $_SESSION['id'] . "'";
$coinsresult = mysql_query($coins);

if($coinsresult) {
$_SESSION['coins'] = $cashresult;

echo "";
} else {
echo "Kaufen fehlgeschlagen.";
}

}
else { echo "Kaufen fehlgeschlagen."; }

} else { echo "Du hast zu wenig Coins."; }

} else { echo "Kaufen fehlgeschlagen."; }

} else { echo "Bitte logge dich ein."; }

}

?>

AYUDA POR FAVOR :((