Have you followed the directions here:  https://simple-press.com/docum.....alization/ dont change teh wp constant...

and remember, you need core, theme and plugins...  the majority of translations are probably in your theme since they control the basic look of your forum...

I didn't change the value in the wp-config. See here:

http://www.internetabc.it/area.....4/09/2.png

http://www.internetabc.it/area.....4/09/1.png

One question: jQuery creates problems with simple press? for example if a pre-load it in the same page of the forum.

Check this article. Although the start probably isn't relevant, the end probably is

 thanks and what about the translation error?

You have been given info on the translation question multiple times includimg email...

This forum is not for support requests...

I think this is an error. How should I do in your opinion??

Its translated in the admin translations... it probably makes sense to add it to the front end translations too...  I can make sure that happens in the next version...