Erro No Pdo

seguinte, to fazendo um sistema e ele tá dando um erro na classe do banco de dados, onde eu tento usar o prepare() ele diz que to chamando um método de um não objeto, não sei o que pode ser, enfim, vou deixar as classes:

Model.class.php

<?php
namespace system;
use \system\DB;

Class Model {

	private $conn;
	protected $table;
	public $error;
	public function __construct(){
 $this->conn = DB::init();
	}
	public function setTable($table){
 $this->table = $table;
	}
	private function buildInsert(array $data){
 $columns = null;
 $values = null;
 foreach($data AS $key => $value):
 $columns .= "{$key},";
 $values .= '?,';
 endforeach;
 $columns = (substr($columns, -1) == ',') ? trim(substr($columns, 0, (strlen($columns) -1))) : $columns;
 $values = (substr($values, -1) == ',') ? trim(substr($values, 0, (strlen($values) -1))) : $values;
 $query = "INSERT INTO {$this->table}({$columns}) VALUES({$values})";
 return trim($query);
	}
	private function buildUpdate(array $data, array $condition, $operator = '='){
 $fields = null;
 foreach($data AS $key => $value):
 $fields .= "{$key} = ?,";
 endforeach;
 $where = null;
 foreach($condition AS $key => $value):
 $where .= "{$key} {$operator} ? AND ";
 endforeach;
 $fields = (substr($fields, -1) == ',') ? trim(substr($fields, 0, (strlen($fields) -1))) : $fields;
 $where = (substr($where, -4) == 'AND ') ? trim(substr($where, 0, (strlen($where) -4))) : $where;
 $query = "UPDATE {$this->table} SET {$fields} WHERE {$where}";
 return trim($query);
	}
	private function buildDelete(array $condition, $operator = '='){
 $where = null;
 foreach($condition AS $key => $value):
 $where .= "{$key} {$operator} ? AND ";
 endforeach;
 $where = (substr($where, -4) == 'AND ') ? trim(substr($where, 0, (strlen($where) -4))) : $where;
 $query = "DELETE FROM {$this->table} WHERE {$where}";
 return trim($query);
	}
	public function insert(array $data){
 try {
 $sql = $this->conn->prepare($this->buildInsert($data));
 $count = 1;
 foreach($data AS $value):
 $type = (is_numeric($value)) ? PDO::PARAM_INT : PDO::PARAM_STR;
 $sql->bindValue($count, $value, $type);
 $count++;
 endforeach;
 return $sql->execute();
 }catch(PDOException $e){
 echo "Erro: {$e->getMessage()}";
 }
	}
	public function update(array $data, array $where){
 try {
 $sql = $this->conn->prepare($this->buildUpdate($data, $where));
 $count = 1;
 foreach($data AS $value):
 $type = (is_numeric($value)) ? PDO::PARAM_INT : PDO::PARAM_STR;
 $sql->bindValue($count, $value, $type);
 $count++;
 endforeach;
 foreach($where AS $value):
 $type = (is_numeric($value)) ? PDO::PARAM_INT : PDO::PARAM_STR;
 $sql->bindValue($count, $value, $type);
 $count++;
 endforeach;
 return $sql->execute();
 }catch(PDOException $e){
 echo "Erro: {$e->getMessage()}";
 }
	}
	public function delete(array $where){
 try {
 $sql = $this->conn->prepare($this->buildDelete($where));
 $count = 1;
 foreach($where AS $value):
 $type = (is_numeric($value)) ? PDO::PARAM_INT : PDO::PARAM_STR;
 $sql->bindValue($count, $value, $type);
 $count++;
 endforeach;
 return $sql->execute();
 }catch(PDOException $e){
 echo "Erro: {$e->getMessage()}";
 }
	}
	public function generic($query, $params = false, $all = true){
 try {
 $sql = $this->conn->prepare($query);
 if($params):
 $count = 1;
 foreach($params AS $value):
 $type = (is_numeric($value)) ? PDO::PARAM_INT : PDO::PARAM_STR;
 $sql->bindValue($count, $value, $type);
 $count++;
 endforeach;
 endif;
 $sql->execute();
 if($all)
 return $sql->fetchAll(PDO::FETCH_OBJ);
 else
 return $sql->fetch(PDO::FETCH_OBJ);
 }catch(PDOException $e){
 echo "Erro: {$e->getMessage()}";
 }
	}
}
?>

DB.class.php

<?php
namespace system;

class DB {

	private static $conn;
	public static function init(){
 if(is_null(self::$conn)):
 try {
 self::$conn = new \PDO(DSN, USER, PASS);
 }catch(PDOException $e){
 echo "Erro ao conectar com o banco de dados: {$e->getMessage()}";
 }
 endif;
 return self::$conn;
	}
}
?>

me ajudem, pfv :s