[Samba] Problems with SAMBA

[Marcelo Bossoni]

Hi All,
sorry about this, but i don't know where to take some help about it, then I
will try you.
I am having a freaking error with samba.
I set the samba security level to share, but it still asking for a password
(konqueror and dolphin) and windows machines says that can't have permission
to access the share.
Can you help me with this?
My smb.conf is

[global]
workgroup = CASA
server string = %h server (Samba, Ubuntu)
dns proxy = no
log file = /var/log/samba/log.%m
max log size = 1000
syslog = 0
panic action = /usr/share/samba/panic-action %d
security = share
encrypt passwords = yes
passdb backend = tdbsam
obey pam restrictions = yes
guest account = nobody
invalid users = root
socket options = TCP_NODELAY
map to guest = Bad User
restrict anonymous = no
guest ok = yes
domain master = no
preferred master = no

[DADOS]
path = /media/dados/
read only = yes
available = yes
guest ok = yes

thx for your time and your help.

-- 
Marcelo Marzola Bossoni
****  IC - UNICAMP ****
*******  EC 04  *******
Engenharia de Computação
Tel.: (14) 3474 1160
Tel.: (19) 3342 4752
Cel.: (19) 9765 1919