i am using a pdf library using dompdf i have a problem

[eluser]dinisptc[/eluser]
$this->load->library('pdf');
$this->pdf->load_view('onplans/list_my_projects_avatar',$Ddata);
$this->pdf->render();
// $this->pdf->stream("BEMVINDO.pdf",array("compress" => true));
$filename="teste";
$report_config = $this->config->item('report');
$report_dir=$report_config['upload_path'].$this->projects_model->check_user_id().'/reportpdf/';
print_r($report_dir);
if (!is_dir($report_dir)) {
mkdir($report_dir,0777,true);
}

$pdfoutput = $this->pdf->output();
//$filename = DIR_BASIC.APARENCIA."/".DIR_DEFAULT_UPLOAD."/dompdf/$dir/$filename.pdf";
$filename ="$report_dir/$filename.pdf";
$fp = fopen($filename, "a");
fwrite($fp, $pdfoutput);
fclose($fp);