mysql_num_rows() expects parameter 1 to be resource, boolean given in hatası

<?php
session_start();
include "s.php";


$isim = $_POST['name'];
$oisim = $_POST['nickname'];
$sifre = $_POST['pwd'];
if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
$ip = $_SERVER['HTTP_CLIENT_IP'];
} elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
$ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
} else {
$ip = $_SERVER['REMOTE_ADDR'];
}
$sorgu = mysql_query("select * from kullanicilar where kullanici='".$isim."'");
if( mysql_num_rows($sorgu) == 1 ){

echo 'mkullanici';

}
else {

if($isim!="" or $sifre!="" or $oisim!="") {
if(strlen($isim) < 3) {
echo "gkullanici";
}
elseif(strlen($oisim) < 3) {
echo "gnick";
}
elseif (strlen($sifre) < 5) {
echo "gsifre";
}
else {

$_SESSION["logged"] = "true";
$_SESSION["user"] = $isim;
$_SESSION["pass"] = $sifre;
$_SESSION["guser"] = $oisim;
@mysql_query("INSERT INTO `kullanicilar` VALUES ('".$isim."', '".$sifre."', '".time()."', '".time()."', 'yok', 1, 1, 2, '1', '".$ip."', 'rsim yok', 0, '0', 1, '".$oisim."', 'yok', 'not@gmail.com', 0, 0);");



echo 'basarili';
}

}
else {
echo 'bosalan';
}


}
mysql_close($baglanti);
?>