Smarty Missing Template Name

Hello everyone,

I'm having issues while customizing a css using the template editor. Whenever i click on Save, i get a "Oops" forbidden error (500).

In my php logs i found out this:

PHP Fatal error: Uncaught --> Smarty: Missing template name <-- \n thrown in /var/www/ on line 679

What's that?

It happened suddenly, I have made many modifications on CSS in the past on this CS Cart installation and never experienced anything similar.

CS Cart v 4.3.6

PHP v 5.4.45-0+deb7u5

Thanks for help