i just save the inno script file with the name CreateMasterFolder.iss [...]
What i need now is a vba code to open the above file within access..
You can open it the same way as any other text file.
However, if you want to execute the commands in the file, you must compile the file using the Inno Setup compiler and then run the resulting setup.
I'm asking this because i don't want the user to see what i'm doing during the installation on PC
Because you are installing malware?
Probably not, but you could be. - That's the reason why writing to the Program Files folder requires Administrator permissions. Without these permissions, it will fail. Probably the reason why you had no luck with icacls.
If you really must install into the Program Files folder, build a proper setup that request Administrator permissions when executed. - Most likely you don't have to install into Program Files, and then you shouldn't do it. - Oh, and don't get the idea to put your Access database into Program Files, it will not work for users without administrator permissions.