Hey CloudReady fans!
Some rough news - the Chrome Recovery Utility seems to have introduced a failure mode with the advent of Chrome (browser) 50 on Windows (it seems to still work as expected on Chrome, CloudReady, and Mac).
It seems that UAC (User Access Controls, Window's security settings) can no longer give permission for USB writing.
One possible way to avoid these may be to close Chrome and relaunch as admin, and/or turn off UAC altogether.
If this doesn't work then you should check out these alternative directions that leverage Win32DiskImager. This is a pretty tried and true method, but you'll need to manually unzip for it.