So in order to fix it, you'll have to replace the js file with the new fix they provide. You can download it here :
(EDIT : URL was wrong)
Upload it on your host, in the folder wp-content/themes/lightword/js/
If you're familiar with HTML, there's another way explained on the Cufon website (still the same URL as at the beginning of this post)
Let me know if you encounter any trouble, I'll try to help.