I installed the plugin and it works well. It does not work in the English language with WPML (Finestra sul mondo, error: WP Masonry Posts: Posts No More . )
I used the same shortcode page in Italian.
From version 1.6 it should work fine with WPML. Can you please make sure you have posts in both language ? Or can you please send me the page url where you have setup the masonry code. Please let me know what you have setup in shortcode like category, post type and so on.