Looking for solution

I am looking for something pretty simple.

I would like a program that will run on my Apache server.
I can run this through MySQL.

I need it to let clients log in through a web page and have access to specific folders. After they log in they should see an area with the folders they have permissions to access and no others.

For instance Client ABZ when logged in would have permissions to folders 1,2,4,8 and no others
Client RSA would have access to folders 2,3,4 and no others.

It needs to be very easy for the clients since most of them are not internet savvy.

This should also have an easy administration panel to handle adding, deleting, and granting permissions to users.

There must be a dozen programs that do this.

Thanks in advance,
John :^)