I managed to resolve this for @factorysketcher by updating line 43 in the file cptbc-frontend.php to this:
$args['tax_query'][] = array(
"taxonomy" => "carousel_category",
"field" => "slug",
"terms" => $atts['category'],
"operator" => "IN"
);
You’ll find it’s currently $args['carousel_category'] = $atts['category'];
which apparently stopped working in WordPress version 3.9.2.
Hope that helps!