codeigniter You did not select a file to upload.

This occurs because the field name is missing from the do_upload function.

if($this->upload->do_upload()){
            $data = array('upload_data' => $this->upload->data());
            echo "

";print_r($data);

            //$this->load->view('upload_success',$data);
        } else {
            $error = array('error' => $this->upload->display_errors());
            echo "

";print_r($error);

            //$this->load->view('file_view', $error);
        }

The above code should be:

if($this->upload->do_upload('flyer')){
            $data = array('upload_data' => $this->upload->data());
            echo "

";print_r($data);

            //$this->load->view('upload_success',$data);
        } else {
            $error = array('error' => $this->upload->display_errors());
            echo "

";print_r($error);

            //$this->load->view('file_view', $error);
        }

Add the name of the file field in the do_upload function.