Windows Server 2008 Enterprise Security

hi all.

i upgraded my Serever from Standard to Enterprise and setup a domain.

the reason is that i run a pos (point of sale program). what i am trying to accomplish is make certain files/folder not accessable for some users.

i have one set for those working on tills, a second for debtors/creditors users and third for administrators.

currently, those working on tills can access everything on the server.

i tried settings permissions on the server itself, but when i tested it yesterday, it didn't work.

Anyone that can help?

I heard same issue with one of my friend. May be this link is useful to you Understanding Windows Server 2008 File and Folder Ownership and Permissions - Techotopia