ColorPicker is not a function….

I am trying to implement colorpicker function in the admin zone to choose a color , but it just does not work.
i have place the compatibility mode
var $jx = jQuery.noConflict();
i also have uploaded the file by the
wp_enqueue_script('colorpicker', '/wp-content/plugins/reservations/js/colorpicker.js');

and finally i inserted almost manually (the library in the code)

$url = $pre  . '/wp-content/plugins/reservations/css/start/jquery-ui-1.7.2.custom.css';
    echo '<link rel="stylesheet" type="text/css" href="' . $url . '" />
    ';

I really hope no ONE Had this problem before coause its a pain in ass.. 3 hours googling spent… i am going to bed now , if anyone could help i would apreciate.

Thanks