Ex : 

<li class="isactive"><a href="profile.php?section=essentials&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section essentials'] ?></a></li>

<div id="profile" class="block2col">
    <div class="blockmenu">
        <h2><span><?php echo $lang_profile['Profile menu'] ?></span></h2>
        <div class="box">
            <div class="inbox">
                <ul>
                    <li<?php if ($page == 'essentials') echo ' class="isactive"'; ?>><a href="profile.php?section=essentials&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section essentials'] ?></a></li>
                    <li<?php if ($page == 'personal') echo ' class="isactive"'; ?>><a href="profile.php?section=personal&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section personal'] ?></a></li>
                    <li<?php if ($page == 'messaging') echo ' class="isactive"'; ?>><a href="profile.php?section=messaging&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section messaging'] ?></a></li>
                    <li<?php if ($page == 'personality') echo ' class="isactive"'; ?>><a href="profile.php?section=personality&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section personality'] ?></a></li>
                    <li<?php if ($page == 'display') echo ' class="isactive"'; ?>><a href="profile.php?section=display&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section display'] ?></a></li>
                    <li<?php if ($page == 'privacy') echo ' class="isactive"'; ?>><a href="profile.php?section=privacy&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section privacy'] ?></a></li>
<?php if ($pun_user['g_id'] == PUN_ADMIN || ($pun_user['g_id'] == PUN_MOD && $pun_config['p_mod_ban_users'] == '1')): ?>                    <li<?php if ($page == 'admin') echo ' class="isactive"'; ?>><a href="profile.php?section=admin&amp;id=<?php echo $id ?>"><?php echo $lang_profile['Section admin'] ?></a></li>
<?php endif; ?>                </ul>
            </div>
        </div>
    </div>
<?php

./include/functions.php

Line: 545 -> 550

<li -> <li>

Dante