[Neo_obs]

Thought I would help with the WOL part. You need to create two plugins

Hook Location: online_location_process

if ($filename == '/400_forum.php' || $filename == '400_forum.php')
{
    $userinfo['activity'] = '400error';
}
if ($filename == '/401_forum.php' || $filename == '401_forum.php')
{
    $userinfo['activity'] = '401error';
}
if ($filename == '/403_forum.php' || $filename == '403_forum.php')
{
    $userinfo['activity'] = '403error';
}
if ($filename == '/404_forum.php' || $filename == '404_forum.php')
{
    $userinfo['activity'] = '404error';
}
if ($filename == '/500_forum.php' || $filename == '500_forum.php')
{
    $userinfo['activity'] = '500error';
}

The second
Hook Location: online_location_unknown

if ($userinfo['activity'] == '400error')
{
    $userinfo['action'] = '400 Error Page';
    $handled = true;
}
if ($userinfo['activity'] == '401error')
{
    $userinfo['action'] = '401 Error Page';
    $handled = true;
}
if ($userinfo['activity'] == '403error')
{
    $userinfo['action'] = '403 Error Page';
    $handled = true;
}
if ($userinfo['activity'] == '404error')
{
    $userinfo['action'] = '404 Error Page';
    $handled = true;
}
if ($userinfo['activity'] == '500error')
{
    $userinfo['action'] = '500 Error Page';
    $handled = true;
}

That should do it.

Just did it on my forum and all is working. You may want to put "Viewing 400 Error Page" if that is what you want it to show.