microsoft.public.windowsxp.security_admin

I have six computers on a network which I manage. One of the six will not
allow me to access shared folders. I have taken ownership of the shared
folders and still receive the message "(folder) is not accessible. You might
not have permission to use this network resource .......". All the
workstations have the same permissions but just this one is giving me a
problem.
I found that if I set up Eveyone in the permissions than I gain access, but
this defeats the security necessity.