А в логах что?Рабочий пример, в папку share1 пускает всех без пароля, в папку share2 только с паролем
[global]
dos charset = CP866
display charset = KOI8-R
workgroup = WORKGROUP
netbios name = FS
map to guest = Bad User
null passwords = Yes
passdb backend = tdbsam
log file = /var/log/samba/samba.log
os level = 255
preferred master = Yes
[share1]
comment = Server Side Includes
path = /var/www/ssi
force user = nobody
read only = No
create mask = 0777
force create mode = 0777
directory mask = 0777
force directory mode = 0777
guest only = Yes
guest ok = Yes
[share2]
comment = True crypt keys
path = /usr/local/tc
force user = truecrypt
create mask = 0444
force create mode = 0444
directory mask = 0444
force directory mode = 0444
browseable = No