php code where is the error?

[Yusuf ali]

Code 1 (Class)

public function UyeKayit($adres, $ad, $soyad, $mail, $sifre1, $sifre2, $gsm, $il){
if (filter_var($mail,FILTER_VALIDATE_EMAIL)){
$preg1 = true;
}else{
$preg1 = false;
}
if (preg_match('/^[a-z\d_]{5,20}$/i', $ad)){
$preg2 = true;
}else{
$preg2 = false;
}
if (preg_match('/^[a-z\d_]{5,20}$/i', $soyad)){
$preg3 = true;
}else{
$preg3 = false;
}
if (filter_var($gsm,FILTER_SANITIZE_NUMBER_INT)){
$preg4 = true;
}else{
$preg4 = false;
}
if ($sifre1 === $sifre2 and preg_match('/^[a-z\d_]{5,20}$/i', $sifre1)){
$sifre = md5($sifre1);
}else{
$preg5 = false;
}
if (preg_match('/^[a-z\d_]{5,20}$/i', $il)){
$preg6 = true;
}else{
$preg6 = false;
}
$ip = $_SERVER['REMOTE_ADDR'];
$adres = stripslashes($adres);
$sql = "insert into kullan?c?lar (k_adres,k_ad,k_soyad,k_posta,k_sifre,k_gsm,k_il,k_ip) values ('$adres','$ad','$soyad','$mail','$sifre','$gsm','$il','$ip') ";
if (mysql_query($sql,$this->BaglanDB())){
return $sonuc = true;
}else{
return $sonuc = false;
}
return array($preg1, $preg2, $preg3, $preg4, $preg5, $preg6, $sonuc);
}


-------------------------------------------------

Code 2 (Down)

<?php
require_once('classes/db.class.php');
$veri = array();
$adres = $_POST['adres'];
$ad = $_POST['ad'];
$soyad = $_POST['soyad'];
$mail = $_POST['mail'];
$sifre1 = $_POST['sifre1'];
$sifre2 = $_POST['sifre2'];
$gsm = $_POST['gsm'];
$il = $_POST['il'];

$uyekayit = new DBekle();
list($preg1, $preg2, $preg3, $preg4, $preg5, $preg6, $sonuc) = $uyekayit->UyeKayit($adres,$ad,$soyad,$mail,$sifre1,$sifre2,$gsm,$il);
$uyekayit->UyeKayit($adres,$ad,$soyad,$mail,$sifre1,$sifre2,$gsm,$il);
if ($sonuc == true){
echo "kay?t eklendi";
}
?>


Where is the error?