UPDATE not work, PLZ Help me

[eluser]Leftfield[/eluser]
If i replace like you

<form id="form1" name="form1" method="get" action="/admin/pageedit/<?php echo $id; ?>">

then i ricive on my admin/pageedit/54 action

A PHP Error was encountered

Severity: Notice

Message: Undefined variable: id

Filename: admin/editpage.php

Line Number: 123
">

And when i push the button Edit i ve got

An Error Was Encountered

The URI you submitted has disallowed characters.

and URL via

admin/pageedit/<div style=

Now my code look like:
Controller

Code:

function pageedit($id) {
        $this->load->library('common_lib');
        $this->common_lib->auth();
        $this->load->helper(array('form', 'url'));
        $this->load->library('validation');
        $this->validation->set_rules('textfield', 'textfield', 'required');
        $this->validation->set_rules('textarea', 'textarea', 'required');

//читаем запись из БД
        if (!$this->input->post('textfield') && !$this->input->post('textarea')) {
            $item = $this->Kernel->get($id);

            $this->validation->textfield = $item['title'];
            $this->validation->textarea = $item['fulltext'];
        }
        $data = array();
        $CI = &get;_instance();
        $title = $CI->config->item('admin_title');
        $author = $CI->config->item('admin_login');
        $data['title'] = $title;

        if ($this->validation->run() == FALSE) {
            $this->load->view('admin/editpage', $data);
        }
        else {

            $data = array(
                    'title' => $this->input->post('textfield'),
                    'fulltext' => $this->input->post('textarea'),
                    'date' => date('Y:m:d')
            );
            $id = $this->input->post('id');
            $this->Kernel->update($id, $data);
            redirect('/admin/browsepages/');
        }
    }

Model

Code:

function update($id, $data) {
        $this->db->where('id', $id);
        $this->db->update('stand_alone_pages',$data);
      
    }

View

Code:

<form id="form1" name="form1" method="post" action="/admin/pageedit/<?php echo $id ?>">

                                    <p>
                                        &lt;input name="textfield" type="text"   value="&lt;?php echo form_prep(@$this-&gt;validation->textfield)?&gt;" size="60" />
                                    </p>
                                    <p>
                                        &lt;textarea name="textarea"&gt;&lt;?php echo form_prep(@$this->validation->textarea)?&gt;&lt;/textarea&gt;
                                    </p>
                                    <p>
                                        &lt;input type="submit" name="Submit" value="Редактировать" /&gt;
                                    </p>
                                &lt;/form&gt;

Plz can you show me right way, im gone insane I really want to make it work