Try change mctagmap_functions.php
elseif($from_category){
$url =esc_attr( get_tag_link( $tag->term_id )).’?mctmCatId=’.$from_category.’&mctmTag=’.$tag->slug;
}
to
elseif($from_category){
$url =esc_attr( get_tag_link( $tag->term_id )).’&cat=’.$from_category;
}
It worked on me, using WP 3.6.1 and Twenty Thirteen theme 🙂
