$config['upload_path'] = site_path().'photos/';
$config['allowed_types'] = 'gif|jpg|png|jpeg';
$config['max_size'] = '2048';
$this->load->library('upload', $config);    
if ( ! $this->upload->do_upload())
{ 
    $this->data['alert'] = $this->upload->display_errors();                     
    $this->load->view('profile/photo', $this->data);
}   
else
{
    $upload_data = $this->upload->data();

    $filename = $upload_data['file_name'];
    $width = $upload_data['image_width'];
    $height = $upload_data['image_height'];
    $config1 = array();
    $this->load->library('image_lib');
    $config1['source_image'] = site_path().'photos/'.$filename;


    $this->remove_existing_file($this->session->userdata('user_id'));
    $this->Profile_model->savephoto('Edit', $filename );
    redirect('/profile/photo');
}

Estou recebendo este erro

O caminho do upload não parece ser válid