Issue with active record update in CodeIgniter

I have a form that submits data to a database in a CodeIgniter app (CI v. 2.0.2). We are allowing users to "edit" records by having them resubmit a record with new values and then doing an update. On submit, the form calls the vote controller's create method. Inside the create method, we check to see if there's already a record based on an entry code and the user's ID. If there is, we update; otherwise we create a new record. The creation works just fine; it's only the update I'm having an issue with. Here's the code.

view

<div id="vote_form">
            <?php
           $hidden = array('dot_judge_id' => $this->session->userdata('dot_judge_id'));

            echo form_open('vote/create'); 
                $entry_code_data = array(
                    'name' => 'entry_code',
                    'id' => 'entry_code',
                    'value' => set_value('entry_code')
                );

                echo form_hidden($hidden);

                $score_options = array('1'=>'1 (lowest)', '2'=>'2','3'=>'3', '4'=>'4','5'=>'5 (highest)');

                ?>
                <p><label for="entry_code">Entry code: </label><?php echo form_input($entry_code_data); ?></p>
                <p><label for="q1">Question 1: </label><?php echo form_dropdown('q1', $score_options, ''); ?></p>
                <p><label for="q2">Question 2: </label><?php echo form_dropdown('q2', $score_options, ''); ?></p>
                <p><label for="q3">Question 3: </label><?php echo form_dropdown('q3', $score_options, ''); ?></p>
                <p><label for="q4">Question 4: </label><?php echo form_dropdown('q4', $score_options, ''); ?></p>
                <p><label for="q5">Question 5: </label><?php echo form_dropdown('q5', $score_options, ''); ?></p>

                <p><?php echo form_submit('submit', 'Submit vote'); ?></p>                

            <?php echo form_close(); ?>
            <?php echo validation_errors(); ?>


        </div>

controller

function create() {
                $id = $this->input->post('entry_code');
                $judge_id = $this->input->post('dot_judge_id');

        $data = array(
            'entry_code' => $id,
            'dot_judge_id' => $judge_id,
            'q1' => $this->input->post('q1'),
                        'q2' => $this->input->post('q2'),
                        'q3' => $this->input->post('q3'),
                        'q4' => $this->input->post('q4'),
                        'q5' => $this->input->post('q5'),

        );

                //first check to see if there's already a record for this judge/entry
                //if so, update. Otherwise, insert
                $vote_id = $this->vote_model->getEntryById($id, $judge_id);
                if($vote_id) {
                        log_message('debug', 'vote id exists: '.$vote_id);
                        $this->vote_model->updateRecord($data, $vote_id);

                }
                else {
                        log_message('debug', 'vote id does not exist; creating new');
                        $this->vote_model->createRecord($data);
                }

                /*
                 after submission, go to another page that gives choices - review entries, submit another entry, log out
                */
                $data['msg'] = "Entry submitted";
        $this->menu();

    }

model

function getEntryByID($id, $judge_id) {
        //determine if record already exists for entry/judge
        $sql = 'SELECT vote_id from dot_vote WHERE entry_code = ? AND dot_judge_id = ?';
        $query = $this->db->query($sql, array($id, $judge_id));

        if($query->num_rows() == 1) {
               $row = $query->row();
               return $row->vote_id;
        }
         else {
            return false;
         }
    }


    function createRecord($data) {
        $this->db->insert('dot_vote', $data);
        return;
    }

    function updateRecord($data, $vote_id) {
        log_message('debug', 'vote id is passed: '.$vote_id);
        $this->db->where('vote_id', $vote_id);
        $this->update('dot_vo开发者_JAVA技巧te', $data);
    }

I know it's making it into the updateRecord method because the log_message output is in my log file displaying the correct vote_id (the auto-increment field of the returned record). But what I get in the browser is the following:

Can anyone point me in the right direction here? I have error display on in my config file, and have gotten SQL errors when they occur, so I don't think this is a SQL error. But I have no idea what could be happening in that tiny little function that's causing this. My next step is to skip the active record update and just use a standard query, but I'd like to know what's causing the problem here, even if I can get it to work the other way.

This line stood out:

$this->update('dot_vote', $data);

Do you mean this?

$this->db->update('dot_vote', $data);