Do you have icacls.exe in your system32 folder(usually in c:\windows\system32)? If you have it, is your windows path setup in a way that lets you access icacls.exe? You can check by opening a command prompt to any folder, except for c:\windows\system32, and typing following command:
icacls /?
If you see help info for icacls.exe then you are good. If you see ‘icacls’ is not recognized as an internal or external command then we have a problem. You’ll need to make sure your System Variables Path has your system32 folder in it.