Facebook does not appear on some posts?

For some reason the facebook like / facebook share buttom does not appear on certain posts. What could be causing this?

Works on this post (and most posts)

http://www.glasgowvant.com/glasgow-green-fireworks-guy-fawkes/

Doesn’t work on this post (and a few others)

http://www.glasgowvant.com/christmas-lights-switch-on-in-george-square-glasgow/

http://wordpress.org/extend/plugins/wordpress-social-ring/