Cannot modify header information

[eluser]Nathan Payne[/eluser]
[quote author="Armchair Samurai" date="1227253725"]Perhaps this is far too obvious a question, but what's on line 37 in Layout.php? From the errors, sounds like it's outputting something to the browser.[/quote]
Layout.php is below.
I have hunted the files for blank space etc.

Code:

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
class Layout
{
    
    var $obj;
    var $layout;
    
    function Layout($layout = "layout_main")
    {
        $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);
        }
    }
}