Does the problem only happen with IT localization? It looks like templates still work on the demo site.
If all else fails, I suggest use web.config to configure the previous version of TinyMCE which should still be on disk.
TinyMCE is transitioning to a complete rewrite in version 4.x and I think they have introduced bugs into 3.5.8 as a result. This problem with the localization files needing to be in 2 places is an example.
I was going to update to their new 4.x release but so far I am unable to get the file browser working with that version and they have not updated their documentation well enough yet.