do shortcode not working

hello i have big problem here, if im putting the do_shrocode funtion on my single.php its not working but on my plugin’s template and post/page editor it working.. i dont know what’s wrong. its displaying nothing..

<?php
if ( have_posts() ) : while ( have_posts() ) : the_post();
		?>
 			<div class="blog-post" style="margin-left: 207px; margin-top: -20px;">

				<h2 class="titel"><?php the_title();?></h2>

				<div class="blog-content">

					<div class="feat-img">

					<?php if(has_post_thumbnail) { the_post_thumbnail('thumbnail');} ?> 

					</div>
					<?php
							$urlbox = get_video_box();

							echo $urlbox[0]; // echo out the url of a post
							echo $urlbox[1]; // echo out the url description of a post
							echo do_shortcode('[jwplayer config="Out-of-the-Box" file="' . $urlbox[0] . '" image="http://www.mywebsite.com/myimage.jpg"]');
							?>
					<?php the_content(); ?>
				</div>
			<div class="clear"></div>
			</div>
 		<?php endwhile;
 		 endif; ?>