permissions changed automatically!

Hello. I have created a directory called "/home/All" so as to establish
a folder inside it to use with Samba (allowing the access to everybody).

So I have created also "/home/All/Documents/" and have typed this comands:

chmod 777 /home/All/
chmod 777 /home/All/Documents/
chown nobody:nogroup /home/All/
chown nobody:nogroup /home/All/Documents/

That's how I have changed permissions and propietaries. After this, I
configure smb.conf to share the folder and everything is Ok.

After some minutes, I can see that I cannot access the shared directory,
with my Windows client, and then if I make "ls -la" I can see that the
permissions of the directory /home/All/ have changed, and I have to do
again a chmod to make it work.

Does anyone know what happens? I am using Mandrake 9.2 RC2 with Samba
2.2.8a (my filesystem is ext3).

Thanks in advance!