update to 4.1.1-it – fileperms() [function.fileperms]: stat failed

Hi, I can’t update wp to new version
(4.1.1-it from 4.1).
I see this error: “Warning: fileperms() [function.fileperms]: stat failed for D:\Inetpub\webs\diambrisrlit/ in D:\Inetpub\webs\diambrisrlit\wp-admin\includes\file.php on line 868 – Can not find the root directory of WordPress.
Installation failed”

I see in my control pannel and I have Read/Execute and Write permission.
My manteiner is aruba (https://www.aruba.it/en/home.aspx) and the server is windows

What can I do?

Thanks
Alessandro