Form action problem, duplicated URL

[eluser]kulldox[/eluser]
I'm creating a simple login form. Working on local server.
The site is in

Code:

http://www.kullcms.local/admin/

Facing a problem with form's action in

Code:

views/login.php

.
Have the following:

Code:

<form action="/admin/zone" method="POST" id="loginform">
    <label for="username">Username:</label>
    &lt;input type="text" name="username" id="usr" value="&lt;?php echo set_value('username'); ?&gt;" /&gt;
    &lt;?php echo form_error('username'); ?&gt;<br /><br />
    
    <label for="pwd">Password:</label>
    &lt;input type="password" name="password" id="pwd" value="&lt;?php echo set_value('password'); ?&gt;" /&gt;
    &lt;?php echo form_error('password'); ?&gt;<br /><br />
    
    <label for="pwd"></label>
    &lt;input type="submit" value="Login" name="login" id="submit_butt" /&gt;
&lt;/form&gt;

But after submitting it goes to

Code:

http://www.kullcms.local/admin/www.kullcms.local/admin/zone

.

It's very strange strange.

My config/config.php :

Code:

$config['base_url']    = $_SERVER['SERVER_NAME'].'/admin';
$config['index_page'] = "";

Notice? the url is duplicated(actually the base_url is duplicated) and I don't understand why and where this happens.
Anybody?

FYI, I'm pretty new to CI but experienced enough with PHP

Thanks in advance