correct file/folder permission setting for a nsis installer subprocess

[hellik]

> Are some of these 64-bit and some 32-bit versions of Windows?

it works for me for win 7 32-bit and 64-bit; users reported that it doesn't work for win 8/win 10 64-bit.

> You should also check if AccessControl failed:

added it to the nsis script, waiting for the daily build of the installer and report back

> You could also try granting FullAccess

will try it