Ersetze mit:

HTML-Code:
menuehead("Login");?>
<form action="" method="post">
    <b>Nickname:</b><br />
    <input type="text" name="nickname" value="<?=$_POST['nickname'];?>" placeholder="Username"><br>
    <b>Passwort:</b><br />
    <input type="Password" name="passwort" value="Passwort"  placeholder="Passwort"><br>
    <a href="?content=/intern/daten">Passwort vergessen?</a>

    <select name="autologin" size="1">
        <option value="true" SELECTED>Mit Autologin&nbsp;</option>
        <option value="false">Ohne Autologin&nbsp;</option>
    </select><br>
    <br>
    <input type="submit" name="checkid" value="Login" style="width: 115px; height: 33px; background-image: url(images/einloggen.png); text-indent: 999px; border: none"><br><br>

    Noch nicht registriert?<br>
    Dann aber schnell!<br>
    <br />
    <a href="?content=/intern/anmelden"><img src="images/registrieren.png" border="0"></a>
</form>
<?}?>
<?menuefoot();?>