FB 'Like Box' shows errors on all URLs submitted on a page

Hi there,

I'm trying to add Facebook 'Like Boxes' to some of my sub pages that contain articles. I drag the 'Like Box' icon over to the bottom of the page under the article and the dialogue box asks for the Facebook URL. I copy the Facebook URL that I want into the dialogue box, directly from the address bar and it seems to be consistent to what the dialogue box asks for, but whenever I submit it, it just shows up as an error in red, saying its not an actual valid Facebook URL. But what else is it if it has been copied directly from the FB address bar?

I have a screengrab of it but not sure how to submit it to you. Can you let me know if its a bug or if there is something more I need to know about Facebook URLs - I'm just copying the address over.