Probleme avec mon site

<ul>
                                <TABLE >
                                            <TR>
                                                 
                                               <?php 
                                $req_join1 = 'SELECT *
                                FROM catalogue
                                 WHERE statu_cata=1 order by lib_cata';
                                //print_r($req_join1);
                                $envoi1 = $bd->query($req_join1);
                                while ( $data1 = $envoi1->fetch()) {
                                echo '<TD><img src="ca/pages/catalogue/img/'.$data1['img_cata'].'"></TD>';}?>
                            
                                            </TR>
                                             <TR>
                                              <?php 
                                $req_join1 = 'SELECT * FROM catalogue WHERE statu_cata=1 order by lib_cata';
                                //print_r($req_join1);
                                $envoi1 = $bd->query($req_join1);
                                while ( $data1 = $envoi1->fetch()) {
                                echo '
                                <TD><a class="mega-title" href="index.php?&code='.$data1['id_cata'].'&page=Allproduct.php" rel="nofollow noopener noreferrer" target="_blank">'.$data1['lib_cata'].'</a> <li></TD>';}?>
                            
                                    </TR>
                                              
                                    </TABLE>

                           </ul>
                        </div>
                        <div class="menu-block-3 hidden-sm">
                          <div class="mega-menu-img"> <a href="index.php?page=about.php" rel="nofollow noopener noreferrer" target="_blank"></a> </div>
                        </div>
                      </div>
                    </div>
                  </li>
                  <?php if (isset($_GET['page']) AND $_GET['page']=="about_us.php") {echo'<li class="active">'; }
                  else echo'<li>';?><a href="index.php?page=about_us.php" rel="nofollow noopener noreferrer" target="_blank">A propos</a>
                    
                  </li>
                  <?php if (isset($_GET['page']) AND $_GET['page']=="contact.php") {echo'<li class="active ">'; }
                  else echo'<li >';?><a href="index.php?page=contact.php" rel="nofollow noopener noreferrer" target="_blank">Contactez nous</a></li>
                </ul>

 <?php if (isset($_GET['page']) AND $_GET['page']=="about_us.php") {echo'<li class="active">'; }
                  else echo'<li>';?><a href="index.php?page=about_us.php" rel="nofollow noopener noreferrer" target="_blank">A propos</a>
                    
                  </li>
                  <?php if (isset($_GET['page']) AND $_GET['page']=="contact.php") {echo'<li class="active ">'; }
                  else echo'<li >';?><a href="index.php?page=contact.php" rel="nofollow noopener noreferrer" target="_blank">Contactez nous</a></li>
                </ul>

 //récupération PROPRE des variables AVANT de les utiliser !
 $page = !empty($_GET['page']) ? $_GET['page'] : NULL;
 
 echo '<li class="'.$page == "about_us.php" ? "active" : "".'"><a href="index.php?page='.$page.'>A propos</a></li>';
 echo '<li class="'.$page == "contact.php" ? "active" : "".'"><a href="index.php?page='.$page.'>Contactez nous</a></li>';
 echo '<li class="'.$page == "Allproduct.php" ? "active" : "".'"><a href="index.php?page='.$page.'>Tous les produits</a></li>';
   
   

<a class="mega-title" href="index.php?&code='.$data1['id_cata'].'&page=Allproduct.php" rel="nofollow noopener noreferrer" target="_blank">'.$data1['lib_cata'].'</a> <li 

<?php 
 if (isset($_GET['page'])) {
  $page=$_GET['page'];
  include $page;
 
       } else
                  {
 
                    $page='home.php'; 
                    
                    include $page; 

                 } 
   ?>

<a class="mega-title" href="index.php?&code='.$data1['id_cata'].'&page=Allproduct.php" rel="nofollow noopener noreferrer" target="_blank">'.$data1['lib_cata'].'</a>

&code=

href="index.php?page=contact.php"

href="contact.php"

<?php 

//recupération PROPRE des variables AVANT de les utiliser (je radote..mais tu n'en tiens visiblement toujours pas compte !!!! =
//bref :
$page = !empty($_GET['page']) ? $_GET['page'] : 'home.php';

 //on vérifie que la page existe et n'est pas juste un dossier et que tu as les droits en lecture:
 if(file_exists($page) && !is_dir($page) &&  is_readable($page)){
   include_once $page;
 }else{
   echo "<br>Erreur. La page <i>".$page."</i> est introuvable ou les droits sont insuffisants !";
 }
?>