Site with different layout structures

[eluser]explores[/eluser]
Hi,
I am new to CI and I am trying to figure out how to setup certain pages to use a different layout, for example some pages will use a one column and others will use a two column structure. Currently I have a layout.php in the libraries folder and its set to read a layout.php in the views folder which works fine but when I try to repeat the process for the other layout I get an error message. I have searched the wiki, forum, guide, and Google but nothing I read seems like the correct solution.

Any help would be great
Thanks

ERROR
A PHP Error was encountered
Severity: Notice
Message: Undefined property: Port::$layout
Filename: controllers/port.php
Line Number: 15

libraries Folder:
File: Layout_one_column
CODE:

Code:

<?php  
if (!defined('BASEPATH')) exit('No direct script access allowed');

class Layout_one_column
{
    
    var $obj;
    var $layout;
    
    
    function Layout($layout = "layout_one_column")
    {
        $this->obj =& get_instance();
        $this->layout = $layout;
    }

    function setLayout($layout)
    {
      $this->layout = $layout;
    }
    
    function view($view, $data=null, $return=false)
    {
        $loadedData = array();
        $loadedData['content_for_layout'] = $this->obj->load->view($view,$data,true);
        
        if($return)
        {
            $output = $this->obj->load->view($this->layout, $loadedData, true);
            return $output;
        }
        else
        {
            $this->obj->load->view($this->layout, $loadedData, false);
        }

        }
}
?>

Controllers Folder:
File: port.php
Code:

Code:

<?php

class Port extends Controller
{
    function Port()
    {
        parent::Controller();
        
        $this->load->helper('url');
    }
    function index()
    {
        $data['title_for_layout'] = "Website Portfolio | Florida Web Design Company | Last 7 Studios";
        $this->load->library('Layout_one_column','layout_one_column');
        $this->layout->view('/port/port_view', $data);
        }

    }
?>