mysql_fetch_assoc（）需要解决

Question

我已经正确添加了mysql数据库，在创建之后，我收到如下错误消息：

Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in C:\xampp\htdocs\bcm\index.php on line 20

我的代码是：

<?php
/*
*
* Create Download Link
* Jaocb Wyke
* jacob@frozensheep.com
*
*/

//connect to the DB
$resDB = mysql_connect("localhost", "", "");
mysql_select_db("bedsitedownload", $resDB);

function createKey(){
    //create a random key
    $strKey = md5(microtime());

    //check to make sure this key isnt already in use
    $resCheck = mysql_query("SELECT count(*) FROM downloads WHERE downloadkey = '{$strKey}' LIMIT 1");
    $arrCheck = mysql_fetch_assoc($resCheck);
    if($arrCheck['count(*)']){
        //key already in use
        return createKey();
    }else{
        //key is OK
        return $strKey;
    }
}

//get a unique download key
$strKey = createKey();

//insert the download record into the database
mysql_query("INSERT INTO downloads (downloadkey, file, expires) VALUES ('{$strKey}', 'onetimedownload.zip', '".(time()+(60*60*24*7))."')");

?>

如何解决这个mysql_fetch_assoc（）问题？