Set Security Permission by Powershell

Hi,

i have a portable Tool that i wanna deploy for alle Employees. 

1. I put the tool under ../programdata

2. Put an link to the public desktop 

3. Here is stuck. I want to change the permissons of the user to a file in the toolfolder. For this i try to use Powershell but it does not work. The user should have Write permissions so all changes to the tool will be saved. Otherwise he close the programm and all changes get lost.

Here what i tryed:

$acl = Get-Acl "C:\ProgramData\PDFXEdit8_Portable\Settings.dat"
$accessRule = New-Object System.Security.AccessControl.FileSystemAccessRule("Benutzer","Write","Allow")
$acl.SetAccessRule($accessRule)