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

Hej!

Har et problem med følgende kode :
mysql_num_rows() expects parameter 1 to be resource, null given in

Hvor fejler jeg henne?


  public function priv_listrls($line, $args) {

    $channel = $line ['to'];
   
    // failsafes ...
    if (strpos ( $channel, "#" ) === false)
    return;
    if ($channel != $this->precfg["rss"])
    return;

    $sql = "SELECT ctime, rss, nick FROM ".$this->precfg["rssdb"]." ORDER BY ctime DESC";
    $qres = $this->db->query("$sql");
    if (mysql_num_rows($qres) > "0") {
    while ($a = mysql_fetch_assoc($qres)) {
    $this->ircClass->privMsg ( $channel, "7RLS: $a[rss] :: 7Added By: $a[nick]");
    }
    } else {
    $this->ircClass->privMsg ( $channel, "4databasen er tom");
    }
  }