My website is on a win server 2012, using IIS
This explains why the plugin can’t change the folder permissions. The windows-type file systems don’t support the chmod command and the octal representation of folder permissions. We use these things to change the folder permissions on systems running linux or similar.
There are ways to change your folder permissions on your IIS system but you will need to do it manually because it cannot be done via this plugin. Ask your host provider for more info or google will give you the answer.
I think in a future update I will put in some code to detect cases where there is a windows server installation and then inform the user that they cannot use that feature for such environments.
ps: Ignore the 0777 and 0666 values which are displayed by this plugin because these are meaningless for windows file systems due to the reasons explained above.