Running 2 NW6.5sp2 servers and 3 NW5.0 servers.

I have several contexts inside my tree. I added a user inside a context
and I only want this user to have access to 1 folder on one of the NW5.0
servers. Thats it. I don't want this user to be able to see ANYTHING
else on the network like how many servers I have, contexts, etc.

Well, logged in as this user, in Windows Explorer I can see the tree, I
can expand the tree and see the entire kittenkaboodle! Whats interesting
is that on one NW6.5 server called 2LAWN i can expand volume 1, but not
volume 2. On another server NW5.0 called 3LAWN I cannot expand sys, can
expand vol1 but will only see this user's folder. 2LAWN is off root,
and 3LAWN is inside another context separate from the context I placed
the user in.

So I know its a rights issue, but where do I look to remove this
particular user from being able to see these servers off root?