No.

I'll read, but i don't understand why after 1 month with no problem, now i get this problem.

I can change desktop background only opening an image and choose "set as wallpaper", but if i want a loopable wallpaper i have to do this for each screen...

Ok i read, and so? In the manual says that i've to go in desktop menu and choose desktop background, but in my case nothing appens....