[Samba] denied access to windows shares

[silvano]

samba 3. on RedHat 8
Samba is running as a domain controller and is correctly authenticating
domain logon and access to Samba shares from windows client machines.
BUT.
windows clients, both 9x and NT can not "always" access each others shares.
for example:
a windows XP or 9x machine can not always connect to a share on another
Windows XP or 98 machine and vice versa but can always access the Samba
Shares and can always logon to the domain.
the problem is intermitent and only occurs on windows shares not our samba
shares which work fine. somethies i can access and sometimes i get access
denied.
\\computer is not accessable. you might not have permission to use this
network resource.  contact...

this is not a network problem! i am 100% sure of that.

i am confident the share permissions and secutity are correctly set on the
windows shares. this is confirmed in that sometimes i get access.

Does anyone know whats might cause this behaviour?

smb.conf---->
[global]
idmap backend =ldap:ldap://localhost
passdb backend =ldapsam
;SAMBA LDAP declarations
ldap suffix = dc=xxxxx,dc=org,dc=uk
ldap machine suffix = ou=Computers
ldap user suffix = ou=Users
ldap admin dn = "cn=Manager,dc=xxxxx,dc=org,dc=uk"
ldap ssl = No
ldap delete dn = no
workgroup = domainname
netbios name = chaos
server string = MF File Server
security = user
null passwords = yes
encrypt passwords = yes
;passwd program = /usr/local/sbin/smbldap-passwd.pl -o %u
;passwd chat = *new*password* %n\n *new*password* %n\n *successfully*
;unix password sync = Yes

add group script = /etc/samba/smbaddgrp.sh %g
log file = /var/log/samba/%m.loglog level = 0 ; remember to lower the log
level in real life
max log size = 0
socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
domain logons = yes
os level = 255
preferred master = yes
domain master = yes
dns proxy = No
wins support = yes
public = no
browseable = no
writable = no
logon path = \\%L\profiles\%U
logon script = startup.bat
logon home = \\%L\%U\docs\.profiles
logon drive = H:
interfaces = 192.168.57.200

[homes]
comment = Home Directories
path = /home/%U/docs
read only = no
writable = yes
browsable = no


various other shares....