samba - Nov 2010 - Samba on domain member refuses to work after certain time has passed

Hello,

The configuration files for PDC and the server in question are below. 
Both have Samba 3.5.6 installed, firewalls pass all smb/nmb traffic, 
CentOS 5.5.x86_64 runs on both.

The situation: after the server (DEVSERV in the example below) starts 
its Samba, it works fine for approx 1-1.5 days. After that it abruptly 
stops servicing any shared resources. The only cure is to stop Samba, 
erase *.tdb files from /etc/samba and /var/lib/samba, join the domain anew -

net rpc join -SPDC -Uroot

and restart the Samba. After that, it works perfectly for 1-1.5 days again.

I have noticed the following lines today in the DEVSERV's 
/var/log/samba/log.nmbd:

[2010/11/11 15:42:45.748362,  0] 
nmbd/nmbd_nameregister.c:137(register_name_response)
   register_name_response: WINS server at IP 10.1.0.10 rejected our name 
registration of DEVEL<00> IP 10.1.0.12 with error code 5.
[2010/11/11 15:42:45.748439,  0] 
nmbd/nmbd_namelistdb.c:307(standard_fail_register)
   standard_fail_register: Failed to register/refresh name DEVEL<00> on 
subnet UNICAST_SUBNET

May I ask for suggestions on what's to correct?

Thanks.

Configuration files:
PDC, IP 10.11.12.10
eth0's net is 10.11.12.0/24
There are eth0:0, eth0:1, eth:2 I do nto wish to use for Samba (this is 
why interfaces are mentioned)

-------------- PDC smb.conf below ------
[global]
unix charset = UTF8
workgroup = MYDOMAIN
netbios name = PDC
server string = PDC for MYDOMAIN
passdb backend =ldapsam:"ldap://10.11.12.1 ldap://10.11.12.10"
username map = /etc/samba/smbusers
interfaces = eth0 lo
bind interfaces only = yes
log level = 1
syslog = 0
log file = /var/log/samba/%m
max log size = 0
name resolve order = wins bcast hosts
time server = Yes
printcap name = CUPS
add user script = /usr/sbin/smbldap-useradd -m '%u'
delete user script = /usr/sbin/smbldap-userdel '%u'
add group script = /usr/sbin/smbldap-groupadd -p '%g'
delete group script = /usr/sbin/smbldap-groupdel '%g'
add user to group script = /usr/sbin/smbldap-groupmod -m '%g'
'%u'
delete user from group script = /usr/sbin/smbldap-groupmod -x '%g'
'%u'
set primary group script = /usr/sbin/smbldap-usermod -g '%g'
'%u'
add machine script = /usr/sbin/smbldap-useradd -w '%u'
shutdown script = /var/lib/samba/scripts/shutdown.sh
abort shutdown script = /sbin/shutdown -c
logon script = %u.bat
logon drive = W:
logon home = \\%L\%u
logon path = \\%L\profiles\%u
domain logons = Yes
domain master = Yes
wins support = Yes
ldapsam:trusted = yes
ldap ssl = off
ldap suffix = dc=example,dc=com
ldap machine suffix = ou=Computers
ldap user suffix = ou=Users
ldap group suffix = ou=Groups
ldap idmap suffix = ou=Idmap
ldap admin dn = cn=sambaadmin,dc=example,dc=com
idmap backend = ldap://10.11.12.1
idmap uid = 10000-20000
idmap gid = 10000-20000
printer admin = root
printing = cups
-------------- PDC smb.conf above ------

DEVSERV, IP 10.11.12.12

-------------- DEVSERV smb.conf below ------
[global]
workgroup = MYDOMAIN
server string = DEVSERV server`
netbios name = DEVSERV
log file = /var/log/samba/log.%m
max log size = 50
unix extensions = no
security = domain
password server = 10.11.12.1
local master = no
os level = 33
preferred master = no
wins server = 10.11.12.10
dns proxy = yes
load printers = yes
cups options = raw
-------------- DEVSERV smb.conf above ------

Sincerely,
Konstantin