PHP HybridAuth social signin not working at all. Redirecting to ?hauth.start=Facebook&hauth.time

I was trying to make HybridAuth Social Login work on this simple php site. Downloaded HybridAuth and installed it. Then found that even the examples does not work for social login (tried on remote server too.

The normal signin_signup example works fine. But whenever I click the link to login to a social network (i.e, facebook,twitter) it redirects me to (MY_BASE_URL/index.php?hauth.start=Facebook&hauth.time) without showing any login window/error messages at all.

I've carefully read the documentations and other solutions posted here. Adjusted my config.php to have a base url like http://example.com/index.php . But it just does not respond. Is there something I'm missing? I've spent 2 days already on it.

here is my config.php

return 
    array(
        "base_url" => "http://example.com/index.php", 

        "providers" => array ( 
            // openid providers
            "OpenID" => array (
                "enabled" => false
            ),

            "AOL"  => array ( 
                "enabled" => false 
            ),

            "Yahoo" => array ( 
                "enabled" => false,
                "keys"    => array ( "id" => "", "secret" => "" )
            ),

            "Google" => array ( 
                "enabled" => true,
                "keys"    => array ( "id" => "", "secret" => "" )
            ),

            "Facebook" => array ( 
                "enabled" => true,
                "keys"    => array ( "id" => "xxxxxxxxx", "secret" => "xxxxxxx" )
            ),

            "Twitter" => array ( 
                "enabled" => true,
                "keys"    => array ( "key" => "xxxxxxxx", "secret" => "xxxxxxxx" ) 
            ),

            // windows live
            "Live" => array ( 
                "enabled" => false,
                "keys"    => array ( "id" => "", "secret" => "" ) 
            ),

            "MySpace" => array ( 
                "enabled" => false,
                "keys"    => array ( "key" => "", "secret" => "" ) 
            ),

            "LinkedIn" => array ( 
                "enabled" => true,
                "keys"    => array ( "key" => "xxxxxxxx", "secret" => "xxxxxxx" ) 
            ),

            "Foursquare" => array (
                "enabled" => false,
                "keys"    => array ( "id" => "", "secret" => "" ) 
            ),
        ),

        // if you want to enable logging, set 'debug_mode' to true  then provide a writable file by the web server on "debug_file"
        "debug_mode" => false,

        "debug_file" => ""
    );

Can someone please help me? I got a feeling that it does not work very good at all after searching the internet for quite a long. If that's the case, can someone point to a better alternative opensource/free social signin library?

Further to tintinboss's own answer, I found I needed to check for hauth_done as well (this was for an example testing Facebook):

if (isset($_REQUEST['hauth_start']) || isset($_REQUEST['hauth_done']))
{
    Hybrid_Endpoint::process();
}

This finally got it working - thank you tintinboss for the useful answer!