Earlier today, Dave H reported that he was getting an error when trying to use the Like button on his website. It appears that this error is widespread and is a bug coming from Facebook. When clicking on “Like” the user will see a red “Error” message and clicking on it will say that the page could not be reached. It seems to affect all newly created Like buttons. So, if you newly install the plugin, it will affect all your posts. If you already have the plugin, all your existing posts should be fine, but any new post should be affected (this includes the Like button on this very post… try it, you’ll probably get the error).
Update: The bug is not marked as resolved yet, but I do not get it anymore. Let me know if you still get it. Also, you can find more info about the bug on this post from Mashable.