help validatore

 <form name="accesso" action="../login/index.php" method="post">
            <div class="title">
                 <input type="hidden" name="action" value="login" />
            </div>
            <div class="title">
                 Username : <input name="user" type="text" size="18" maxlength="60" />
            </div>
            <div class="titlepw">
                 Password : <input name="pw" type="password" size="18" maxlength="60" />
            </div>
            <input type="submit" name="Login" value="Login" onkeypress="return clickButton(event,'login')" class="login" />
            <? if ($verified_user == '' && $action == "login") { ?>
		     <div id="err">Username o passowrd errati</div>
            <? header("Location: http://www.reteluna.it/sottoportali/accesso/admin/login/"); } ?>
             </form>