[Samba] directory "nobody"

[Alberto]

Hello everybody. Samba 2.2.7 on Mandrake 9.2 in a LAN. I need to receive files 
from 3 samba users ( 2 WXP and 1 W2000 ), files that they put in their home 
directory. The problem is that the 3 users can also see
a directory called "nobody" through which they can see all the directories of 
the computer and enter them and read the files when this is not forbidden.
Even if i set the option browseable=no they cannot see that directory but they 
can connect to it doing \\ipaddress\nobody.
I suppose that this is not normal and believe to have made some big 
configuration mistake. Can somebody help me?