[Samba] using probleme

[Nrx]

Hello I use Centos 4.3 and samba installed directly by the OS. Ver
:3.0101462

I have Xp pro sp2. 

On the windows I see the linux folder but as I try to open it it ask for a
password.

On samba I didn't provide any password.

I tried the user and passwd used on my xp session but didn't work.

On the great book http://us2.samba.org/samba/docs/using_samba/  they say to
set up a samba user. On Webmin you can't add any samba user.

So I did like they said : smbpasswd -a jack (or anything) and it says :
Failed to initialise SAM_ACCOUNT for user xx . Does this user exist in your
UNIX database ? Failed to modify password entry for user xx.

whatever it's a real unix user or any name  it gives the same error.

What can I do ?

Thanks a lot.

 

Ted