"Trying to Access array offset on Value of type bool in..." hatası

<span class="section"><?= $Urun['urun_adi']?></span>

<?php
include"ust.php";

if(!isset($_GET['id']))
 $_GET['id']=0;

$Urun=$db->prepare("SELECT * FROM urun WHERE urun_id=? ");
$Urun->execute(array(intval($_GET['id'])));

$Urun=$Urun->fetch();
 ?>
 <!-- page content -->
 <div class="right_col" role="main">
 <div class="">
 <div class="page-title">
 <div class="title_left">
 <h3>Ürünler</h3>
 </div>

 </div>
 <div class="clearfix"></div>

 <div class="row">
 <div class="col-md-12 col-sm-12 col-xs-12">
 <div class="x_panel">
 <div class="x_title">
 <h2>Ürün Detayı</h2>
 <ul class="nav navbar-right panel_toolbox">
 <li><a class="collapse-link"><i class="fa fa-chevron-up"></i></a>
 </li>

 <li><a class="close-link"><i class="fa fa-close"></i></a>
 </li>
 </ul>
 <div class="clearfix"></div>
 </div>
 <div class="x_content">

<?php
if(isset($_GET['Durum']))
{
if($_GET['Durum'])
 {
?>

 <div class="alert alert-success alert-dismissible fade in" role="alert">
 <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">×</span>
 </button>
 <strong>Güncelleme Yapıldı</strong>
 </div>

<?php
 }
 else.
 {
?>

 <div class="alert alert-danger alert-dismissible fade in" role="alert">
 <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">×</span>
 </button>
 <strong>Güncelleme Yapılamadı</strong>
 </div>

<?php
 }

}
 ?>

 <form action="urun_guncelle.php" method="POST" class="form-horizontal form-label-left" novalidate>
 <span class="section"><?= $Urun['urun_adi']?></span>

 <input type="hidden" name="urun_id" value="<?php echo $Urun['urun_id']?>">

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_adi">Ürünün Adı</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_adi" name="urun_adi" value="<?php echo $Urun['urun_adi']?>" placeholder="Ürünün adını giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_aciklama">Açıklaması</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_aciklama" name="urun_aciklama" value="<?= $Urun['urun_aciklama'] ?>" placeholder="Ürünün açıklamasını giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_fiyat">Fiyat</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_fiyat" name="urun_fiyat" value="<?= $Urun['urun_fiyat'] ?>" placeholder="Ürünün fiyatını giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_indirim">İndirim Oranı(%)</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_indirim" name="urun_indirim" value="<?= $Urun['urun_indirim'] ?>" placeholder="Ürünün indirim oranını giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_stok">Stok Miktarı</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_stok" name="urun_stok" value="<?= $Urun['urun_stok'] ?>" placeholder="Ürünün stok miktarını giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_vitrin">Vitrin Durumu</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_vitrin" name="urun_vitrin" value="<?= $Urun['urun_vitrin'] ?>" placeholder="Ürünün vitrin durumunu giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_kategori_id">Kategori</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_kategori_id" name="urun_kategori_id" value="<?= $Urun['urun_kategori_id'] ?>" placeholder="Ürünün kategorisini giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_renk">Renk</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_renk" name="urun_renk" value="<?= $Urun['urun_renk'] ?>" placeholder="Ürünün rengini giriniz." required="required" type="text">
 </div>
 </div>

 <div class="item form-group">
 <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_marka">Marka</label>
 <div class="col-md-6 col-sm-6 col-xs-12">
 <input class="form-control col-md-7 col-xs-12" id="urun_marka" name="urun_marka" value="<?= $Urun['urun_marka'] ?>" placeholder="Ürünün markasını giriniz." required="required" type="text">
 </div>
 </div>

 <div class="ln_solid"></div>
 <div class="form-group">
 <div class="col-md-6 col-md-offset-3">
 <button id="send" type="submit" class="btn btn-success">Güncelle</button>
 </div>
 </div>
 </form>
 </div>
 </div>
 </div>
 </div>
 </div>
 </div>
 <!-- /page content -->

 <?php
include"alt.php";
 ?>