mysql_query("UPDATE site_users set user_adres='$user_adres', password='$password', user_cep='$user_cep, ad_soyad='$ad_soyad, iban_no='$iban_no, tc_no='$tc_no', email='$email' where id='$dataid'");
yerine aşağıdaki gibi dener misiniz ?
mysql_query("UPDATE site_users SET user_adres=".$user_adres.", password=".$password.", user_cep=".$user_cep.", ad_soyad=".$ad_soyad.", iban_no=".$iban_no.", tc_no=".$tc_no.", email=".$email." WHERE id=".$dataid);