Problem installing theme: Server file size is different from local file size

Hi, I can’t install the theme in prestashop 1.6.1.1 If i use ftp, i recive “An error has occurred during the file copy. ” error. If i use import zip, i recive “Server file size is different from local file size ” error. I have 777 permison in themes folder. I increase in php.ini the size… and increase too in administration>preferences.
I suspect that is a problem of my prestashop installation, but anyway I need help.
Please let me know as soon how I can solve. Now I can't reinstall all because the shop is actually working (with default-bootstrap 1.0 theme).

Thanks