No Such File Directoy - php

Question

Dont know whats the reason behind because my code wont run. Its say's there's no such file directory but there is and index inside a folder. Does my code or the server?Dont know whats the reason behind because my code wont run. Its say's there's no such file directory but there is and index inside a folder. Does my code or the server?
Please see images below. Thanks!.
https://ibb.co/fKqZ5m
https://ibb.co/cDynQm
code:
navbar.php
<?php include('tooltip.php'); ?>
<div class="navbar navbar-fixed-top navbar-inverse">
<div class="navbar-inner">
<div class="container">
<a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</a>
<div class="nav-collapse collapse">
<ul class="nav">
<li class=""><a rel="tooltip" data-placement="bottom" title="Home" id="home" href="index.php"><i class="icon-home icon-large"></i> Home</a> </li>
<!-- <li class="divider-vertical"></li> -->
<li class="">
<a rel="tooltip" data-placement="bottom" title="Click Here to About" id="login" href="about.php"><i class="icon-info-sign icon-large"></i> About</a>
</li>
<li class="">
<a rel="tooltip" data-placement="bottom" title="Click Here to Admin Login" id="login" href="librarian/index.php"><i class="icon-user icon-large"></i> Admin</a>
</li>
<!--<li class="">
<a rel="tooltip" data-placement="bottom" title="Click Here to Register Member" id="login" href="register_member.php"><i class="icon-user icon-large"></i> Register Member</a>
</li>-->
</ul>
</div>
</div>
</div>
</div>
index.php inside librarian directory.
<?php
include('header.php');
include('navbar.php');
?>
<div class="container">
<div class="margin-top">
<div class="row">
<div class="span12">
<div class="login">
<div class="log_txt">
<p><strong><center>Login</center></strong></p>
</div>
<form class="form-horizontal" method="POST">
<div class="control-group">
<label class="control-label" for="inputEmail">Username</label>
<div class="controls">
<input type="text" name="username" id="username" placeholder="Username" required>
</div>
</div>
<div class="control-group">
<label class="control-label" for="inputPassword">Password</label>
<div class="controls">
<input type="password" name="password" id="password" placeholder="Password" required>
</div>
</div>
<div class="control-group">
<div class="controls">
<button id="login" name="submit" type="submit" class="btn"><i class="icon-signin icon-large"></i> Submit</button>
</div>
</div>
<?php
if (isset($_POST['submit'])){
session_start();
$username = $_POST['username'];
$password = $_POST['password'];
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
$result = mysql_query($query)or die(mysql_error());
$num_row = mysql_num_rows($result);
$row=mysql_fetch_array($result);
if( $num_row > 0 ) {
header('location:users.php');
$_SESSION['id']=$row['user_id'];
}
else{ ?>
<div class="alert alert-danger">Access Denied</div>
<?php
}}
?>
</form>
</div>
</div>
</div>
</div>
</div>

Answer 1

It should be ../librarian/index.php because navbar.php is in a different directory (youth).
Most likely your tree is like this:
htdocs
- librarian
- index.php
- youth
- navbar.php
Using ../ will move you up a directory then you can target librarian.