Cannot declare class ABC, because the name is already in use - php

Question

Here am getting an error like Fatal error: Cannot declare class ABC, because the name is already in use in while listing all controller names and functions in project.In order to get i got an library from surroundings and placed it.library looks like this
<?php
if (!defined('BASEPATH'))
exit('No direct script access allowed');
/***
* File: (Codeigniterapp)/libraries/Controllerlist.php
*
* A simple library to list al your controllers with their methods.
* This library will return an array with controllers and methods
*
* The library will scan the "controller" directory and (in case of) one (1) subdirectory level deep
* for controllers
*
* Usage in one of your controllers:
*
* $this->load->library('controllerlist');
* print_r($this->controllerlist->getControllers());
*
* #author Peter Prins
*/
class ControllerList {
/**
* Codeigniter reference
*/
private $CI;
/**
* Array that will hold the controller names and methods
*/
private $aControllers;
// Construct
function __construct() {
// Get Codeigniter instance
$this->CI = get_instance();
// Get all controllers
$this->setControllers();
}
/**
* Return all controllers and their methods
* #return array
*/
public function getControllers() {
return $this->aControllers;
}
/**
* Set the array holding the controller name and methods
*/
public function setControllerMethods($p_sControllerName, $p_aControllerMethods) {
$this->aControllers[$p_sControllerName] = $p_aControllerMethods;
}
/**
* Search and set controller and methods.
*/
private function setControllers() {
// Loop through the controller directory
foreach(glob(APPPATH . 'controllers/*') as $controller) {
// if the value in the loop is a directory loop through that directory
if(is_dir($controller)) {
// Get name of directory
$dirname = basename($controller, 'EXT');
// Loop through the subdirectory
foreach(glob(APPPATH . 'controllers/'.$dirname.'/*') as $subdircontroller) {
// Get the name of the subdir
$subdircontrollername = basename($subdircontroller, EXT);
// Load the controller file in memory if it's not load already
if(!class_exists($subdircontrollername)) {
$this->CI->load->file($subdircontroller);
}
// Add the controllername to the array with its methods
$aMethods = get_class_methods($subdircontrollername);
$aUserMethods = array();
foreach($aMethods as $method) {
if($method != '__construct' && $method != 'get_instance' && $method != $subdircontrollername) {
$aUserMethods[] = $method;
}
}
$this->setControllerMethods($subdircontrollername, $aUserMethods);
}
}
else if(pathinfo($controller, PATHINFO_EXTENSION) == "php"){
// value is no directory get controller name
$controllername = basename($controller, 'EXT');
// Load the class in memory (if it's not loaded already)
if(!class_exists($controllername)) {
var_dump($controller);
$this->CI->load->file($controller);
}
// Add controller and methods to the array
$aMethods = get_class_methods($controllername);
//var_dump($aMethods);
$aUserMethods = array();
if(is_array($aMethods)){
foreach($aMethods as $method) {
if($method != '__construct' && $method != 'get_instance' && $method != $controllername) {
$aUserMethods[] = $method;
}
}
}
$this->setControllerMethods($controllername, $aUserMethods);
}
}
}
}
// EOF
Here am getting error in the line $this->CI->load->file($controller);.when i call this library in my controller am getting error what i mentioned in title.Is it a problem of php version,Here it is telling that controller class name is already called so it cannot be call again.