Hi,
I can reproduce the issue. Win 7, FF it is not shown, while in Chrome it is shown.
The facebook iframe code looks incorrect to me unless you are trying to like a page on facebook from your website. since in the code below , the url in the query string should be the url of the page where the like button is located, and not a facebook url.
<iframe src="//www.facebook.com/plugins/likebox.php?href=http%3A%2F%2Fwww.facebook.com%2Fpages%2FWotake%2F206525936095381%3Ffref%3Dts&width=420&height=100&colorscheme=dark&show_faces=false&border_color=%23666666&stream=false&header=false&force_wall=false&locale=es_LA" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:420px; height:100px;" allowTransparency="true"></iframe>
this is the way it should look ... I used one of my personal app id's
<iframe src="//www.facebook.com/plugins/like.php?href=http%3A%2F%2Fwotake.es&send=false&layout=standard&width=450&show_faces=false&font=tahoma&colorscheme=light&action=like&height=35&appId=404057446298884" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:450px; height:35px;" allowTransparency="true"></iframe>
I would use the code on this page which will dynamically set the url of each of your pages http://elure.co/43_facebook-like-button-dynamic-url-javascript.htm
Thanks,
Nick