ITALIAN LANGUAGE - moving file it_IT.mo to Atahualpa main folder

Hi everybody, first post!
A total novice of wordpress and a complete primitive with computers.

But I CAN cut and paste a file. However, when attempting to add the file it_IT.mo to the main Atahualpa folder I see a red no-access circle indicating clearly that the operation is not allowed. I saw www.gidibao.net instructions and followed but it doesn't work for the reason above.

I wonder wheter somebody, even in another language, has had the same problem?

Many thanks
Daniele