Permissions problems

I am an ITT tech student. In order to further me education, I have built a small four computer lan. I have an NT server,two 2000 workstations and a duall boot 95/RH linux 7.2 workstation to test and expand what I learn. I also have a girlfreind and 5 kids to use as ginni pig users. But I have run into what i beleive is a permissions problem that affects users and domain users but not administrators. First a program wksCal.exe wont respond when you log off and only administrators have access to brouser plugins like flash(my kids like zoogdisney.com). Can anybody point me in the right direction? These are things i must know before i get to the real world of IT. Thanks