i have load url helper , but when i am trying to load from home page with anchor , it says server dont find

,
my view file home.php
<div id = 'pleft'>
<?php
echo "<img src ='".$mainf['image']."' border = '0' align = 'left' />\n";
echo "<h2>" .$mainf['name']."</h2>\n";
echo "<p>" .$mainf['shortdesc']. "<br/>\n" ;
echo anchor('welcome/product/'.$mainf['id'],'see details') . "<br/>\n";
echo anchor ('welcome/cart/'. $mainf['id'],'buy now') . "</p>\n";
?>
</div>
and my controller welcome.php
<?php
class Welcome extends Controller {
function Welcome()
{
parent::Controller();
}
function index()
{
$data['title'] = "Welcome to desinator";
$data['navlist'] = $this->MCats->getAllCategories();
$data['mainf'] = $this->MProducts->getMainFeature();
$skip = $data['mainf']['id'];
$data['sidef'] = $this->MProducts->getRandomProducts(3,$skip);
$data['main'] = 'home';
$this->load->vars($data);
$this->load->view('template');
}
function product($id){
$product = $this->MProducts->getProduct($id);
if (!count($product)){
redirect('welcome/index','refresh');
}
$data['grouplist'] = $this->MProducts->getProductsByGroup(3,$product['grouping'],$id);
$data['product'] = $product;
$data['title'] = "Claudia's Kids | ". $product['name'];
$data['main'] = 'product';
$data['navlist'] = $this->MCats->getCategoriesNav();
$this->load->var($data);
$this->load->view('template');
}
}
my template.php in view ,
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title><?php echo $title; ?></title>
<link href="<?php base_url();?>css/default.css" rel="stylesheet" type="text/css" />
<script type="text/javascript">
//<![CDATA[
base_url = '<?php base_url();?>';
//]]>
</script>
</head>
<body>
<div id="wrapper">
<div id="header">
<?php $this->load->view('header');?>
</div>
<div id="nav">
<?php $this->load->view('navigation');?>
</div>
<div id="main">
<?php $this->load->view($main);?>
</div>
<div id="footer">
<?php $this->load->view('footer');?>
</div>
</div>
</body>
</html>
my index load perfectly but when ever i clik any link , it cant find the sever ,
Not Found
"The requested URL /codeigniter/welcome/product/1 was not found on this server. " please help me .