why why why does it not work? please help

ok first off i want to thank the author for creating this plugin, but then also stressing me out for a full night haha..

so like many others who have probably given up finding a fix to getting this working, i hope not to follow them to the deletion of the plugin.

all i want to do is show the image that i set as the feature image and add the class array so that i can style the image to my choosing.

i have added the function type to functions.php shown below..

if (class_exists('MultiPostThumbnails')) {
        new MultiPostThumbnails(
            array(
                'label' => 'Secondary Image',
                'id' => 'secondary-image',
                'post_type' => 'post'
            )
        );
    }

and then i wish to display the second feature image on the single post. single.php

<div id="main" class="span12 clearfix" role="main">

					<?php if (have_posts()) : while (have_posts()) : the_post(); ?>

					<article id="post-<?php the_ID(); ?>" <?php post_class('clearfix'); ?> role="article" itemscope itemtype="http://schema.org/BlogPosting">
						<div class="row-fluid">
							<div class="span6">
								<div class="carousel slide carousel-fade" id="Carousel">
									<!-- Carousel items -->
									<div class="carousel-inner">
										<div class="active item">
                                                                                    <?php the_post_thumbnail( 'wpbs-featured', array('class' => 'img-border post-custom-img')); ?>
										</div>
										<div class="item">
                                                                                    <?php if (class_exists('MultiPostThumbnails')) : MultiPostThumbnails::the_post_thumbnail( 'wpbs-featured', array('class' => 'img-border post-custom-img')); endif ?>
                                                                                </div>
									</div>
								</div>
							</div>

http://ww.wp.xz.cn/plugins/multiple-featured-images/