Problem with implementing file uploader into existing form

[eluser]heaversm[/eluser]
Hi - I followed the docs and created a standalone file uploader, but I'm having a little bit of trouble integrating into my pre-existing form. For simplicity's sake, I've left out the validation for now. This is my code:

form:

Code:

<?php echo form_open_multipart('control_form/add_group'); ?>
..
<label for="f_groupphoto">Group Photo</label>
&lt;input type="file" name="f_groupphoto"/&gt;

controller

Code:

function add_group(){
        #Validate entry form information
        $this->load->model('Model_form','', TRUE);        
        
        if ($this->form_validation->run() == FALSE)
        {
            //reload with validation errors
        }
        else
        {
            #Add Group to Database
            $this->Model_form->add_group();
            $this->load->view('view_inc_header');
            $this->load->view('view_form_success');
            $this->load->view('view_inc_footer');
        }
    }

Model:

Code:

function add_group()
    {
        
        $config['upload_path'] = './uploads/groups/';
        $config['allowed_types'] = 'gif|jpg|png';
        $config['max_size']    = '100'; //kb
        $config['max_width']  = '1024';
        $config['max_height']  = '768';

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

$v_groupphoto = $this->upload->data();
//ALSO TRIED THIS: $v_groupphoto = $this->input->post('f_groupphoto');
        
        $data = array(
            'upload_data' => $this->upload->data(),
              ...
        );

        $this->db->insert('groups', $data);
    }

Any idea where I'm going wrong? I get a few errors:

Code:

A PHP Error was encountered

Severity: Notice

Message: Array to string conversion

Filename: mysql/mysql_driver.php

Line Number: 535

and

Code:

A Database Error Occurred
Error Number: 1054

Unknown column 'Array' in 'field list'

INSERT INTO `groups` (`group_photo`, `id`, `tree_index`, `group_name`, `group_desc`, `group_parent`, `group_id`) VALUES (Array, NULL, '5', 'Pearl Jam', '', 'top', 'Pearl_Jam')

Filename: model_form.php

Line Number: 135