I wore my JFBC Joomla 2.5 and always had problem when someone clicked on "Like" was the tag {JFBCLike layout=standard show_faces=1 show_send_button=0 width= action=like font=arial colorscheme=light . It happens that today
I did a clean installation of Joomla 3.0 only the table enjoying the K2, without plugins and components.
The strange thing is that the old links the error continues, only new articles are without the tag. Not a problem in the browser cache, and remembering that my joomla folder, I put everything from scratch, except the images and media.
Important. I had discovered that in joomla 2.5 Sh404 disabling the error stopped.