How to enable tts engine?

i installed the latest version of the distro.
now i need to use the tts function but in configuration page it says " choose an engine: AGI script not found".
i saw that flite is already configured and i also added googletts putting the agi file in the agi folder, but asterisk sees none of them.
how can i fix it?

i fixed the issue on my own removing and reinstalling both tts modules.
now i can choose between flite and googletts but only the first works: in fact with googletts it creates no wav file