Yet another .zip file uploading issue

Code:
public function upload_files()

    {

        //check access 

        $access = $this->_check_auth_admin();

    

    if ($access != 1)

    {

    show_404();

    }

        

        

        

    $type = $this->input->post('type');

    

    //config for file upload class

    $config['upload_path'] = './partner_assets/' . $type;

    $config['allowed_types'] = 'jpg|png|eps|pdf|doc|xls|ppt|txt|ai|psd|zip';

    $config['max_size'] = '0';

    

    //load additional libraries

    $this->load->helper('form');

    $this->load->library('upload', $config);

    

        //set title

        $this->data['title'] = "Materials Upload";

        

        //get navigation

        $this->data['sections'] = $this->navigator->get_navigator_sections($access);

    

    //set options for form elements

    $this->data['form_options'] = array(

    'id' => 'upload_form'

    );

    

    $this->data['name_options'] = array(

    'id' => 'name',

    'name' => 'name',

    'size' => '46',

    'maxlength' => '50'

    );

    

    $this->data['description_options'] = array(

    'id' => 'description',

    'name' => 'description',

    'rows' => '3',

    'columns' => '25',

    'maxlength' => '100'

    );

    

    $this->data['type_options'] = array(

    'slicks' => 'Slicks',

    'logos'  => 'Logos',

    'manuals' => 'Manuals',

    'documents' => 'Documents'

    );

    

    $this->data['usage_options'] = array(

    'web/screen' => 'Web/Screen',

    'print'  => 'Print',

    );

    

    $this->data['active_options'] = array(

    '1' => 'Yes',

    '0' => 'No',

    );

    

    if ( ! $this->upload->do_upload())

    {

    $this->data['message'] = $this->upload->display_errors();

    

    //generate view

    $this->load->view('templates/header', $this->data);

    $this->load->view('templates/sections', $this->data);

    $this->load->view('materials/upload_files', $this->data);

    $this->load->view('templates/footer');

    }

    else

    {

    //set upload data

    $file = $this->upload->data();

    

    $material_object = new stdClass;

    $material_object->name = $this->input->post('name');

    $material_object->description = $this->input->post('description');

    $material_object->type = $this->input->post('type');

    $material_object->thumbnail = '';

    $material_object->file = url_title($file['file_name'], 'underscore', TRUE);

    $material_object->usage = $this->input->post('usage');

    $material_object->active = $this->input->post('active');

    

    if ( ! $this->materials_model->add_materials_data($material_object))

    {

    

    $this->session->set_flashdata($this->upload->display_errors());

    redirect('materials/upload_files', 'refresh');

    

    }

    else

    {

    //set messages

    $this->session->set_flashdata('message', "You did a great job uploading that file!");

    redirect('materials/index', 'refresh');

    }

    }

 

    

    }