Problém s registrací

<?php
require "db.php";

echo "<form method=\"POST\" action=\"reg.php?stranka=pridat\">
<fieldset><legend>Váš účet</legend>
Meno: <input type=\"text\" value=\"$nick\" name=\"nick\"><br>
2 x heslo:
<input type=\"password\" name=\"heslo1\">
<input type=\"password\" name=\"heslo2\"><br>
<input type=\"submit\" name=\"send\" value=\"Registrovat\"><br>
</fieldset>
</form>";

$nick = $_POST['nick'];
$heslo1 = $_POST['heslo1'];
$heslo2 = $_POST['heslo2'];

if($_REQUEST['stranka'] == 'pridat'){

if(!$nick==""){
if(!$heslo1==""){
if(!$heslo2==""){
if($heslo1=$heslo2){
$heslo = sha1($heslo2);

if(!mysql_result(mysql_query("select count(*) from `".users."` where `username`='$nick'"),0))
{
mysql_query("INSERT INTO `".users."` (username,password) VALUES ('$nick', '$heslo')");
echo "<script> alert(\"Registrácia prebehla úspešne.\") </script>";
echo "<meta http-equiv=\"refresh\" content=\"10;url=http://supr.wu.cz/log.php\">";
} else { echo "Tento nick sa už používa."; }
} else { echo "Heslá sa nezhodujú."; }
} else { echo "Nezadali ste kontrolu hesla."; }
} else { echo "Nezadali ste heslo."; }
} else { echo "Nezadali ste nick."; }
}
?>

Warning: mysql_query() [function.mysql-query]: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) in /home/free/wu.cz/s/supr/root/www/reg.php on line 26

Warning: mysql_query() [function.mysql-query]: A link to the server could not be established in /home/free/wu.cz/s/supr/root/www/reg.php on line 26

Warning: mysql_result(): supplied argument is not a valid MySQL result resource in /home/free/wu.cz/s/supr/root/www/reg.php on line 26

Warning: mysql_query() [function.mysql-query]: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) in /home/free/wu.cz/s/supr/root/www/reg.php on line 28

Warning: mysql_query() [function.mysql-query]: A link to the server could not be established in /home/free/wu.cz/s/supr/root/www/reg.php on line 28

<?php
function db_connect()
{
  @$link = mysql_connect('mysql.wu.cz', 'wu_supr', 'heslo');
  if (!$link)
    die("Selhalo");

  @$result = mysql_select_db('wu_supr', $link);
  if (!$result)
    die("Selhalo");

  return true;
}

Warning: mysql_result(): supplied argument is not a valid MySQL result resource in /home/free/wu.cz/s/supr/root/www/reg.php on line 26

<?php
$db_host = "mysql.wu.cz";
$db_user = "wu_supr";
$db_pass = "----";
$db_table = "users";
define("USERS", "users");
$spojenie = mysql_connect($db_host,$db_user,$db_pass);
mysql_select_db($db_table,$spojenie);
mysql_query("SET NAMES cp1250");
?>