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How many blocks are configured?
The adsense allows only three ad units.

You can try this plugin: http://wordpress.org/extend/plugins/appad-manager/

add_action( 'wp_head', 'fb_like_thumbnails' );

function fb_like_thumbnails()
{
global $posts;
$thumb = 'http://logo.png'; //your default img


if (has_post_thumbnail() ) {