W2K Professional cannot join Samba 2.2.4 domain

I've just installed a W2K Professional in a machine, but when I try to join my Samba 2.2.4 domain, the following message is displayed:

"The following error occured validating the name _SMART_
The specified domain either doesn't exist or couldn't be contacted"

When I click in 'My Network Places'->'Entire Network'->'Microsoft Windows Network', '_smart_' and 'workgroup' is displayed, and I can even browse the '_smart_' domain.

I've created the machine account using the following commands:

useradd -d /dev/null -g machines -c 'Machine Account' -s /bin/false -M smart03$

smbpasswd -am smart03

My server is a Slackware Linux 8.0 / kernel 2.4.17.

Here's my smb.conf

[global]
    security = user
    status = yes
    workgroup = _SMART_
    encrypt passwords = yes

    domain logons = yes
    domain master = yes
    preferred master = yes
    domain admin group = @adm
    os level=65
    server string = Intranetworks Server
    wins support = yes

    bind interfaces only = yes
    interfaces = 10.0.0.255/255.255.255.0
    logon drive = x:
    logon script = scripts\%U.bat
    time server = yes

    printing = bsd
    printcap name = /etc/printcap
    printer admin = root
    load printers = yes

    log file = /var/log/samba/log.%m

    lock directory = /etc/samba/var/locks

[netlogon]
    comment = Network Logon Service
    path = /etc/samba/netlogon
    writeable = no
    guest ok = yes

[homes]
   comment = Home Directories
   browseable = yes
   read only = no
   create mode = 0750
   hosts allow = 10.0.0.
   hide files = /Maildir/

[print$]
    path = /etc/samba/printers
    comment = Impressoras
    guest ok = yes
    browseable = yes
    read only = yes
    write list = root

[printers]
   path = /usr/spool/public
   comment = All Printers
   browseable = no
   printable = yes
   public = no
   writable = no
   create mode = 0700
   hosts allow = 10.0.0.