I have been battling with the samba server the last two days. It was 
working just fine and then began to fall apart slowly but surely. From a 
windows box on logon it would tell you no domain server was available 
yadda yadda, but it would still give you access to the smb shares. Then 
it decided to just say no domain server available or you don't have access 
to the server. So I fiddle and get it somewhat working. I can view the smb 
shares from a linux with no problem. smbmount no problem. Then after 
making (I think) no changes the daemon will not stay running.
When I do
/etc/rc.d/init/smb restart
it fails on shutting down and gives ok for starting up.
/etc/rc.d/init smb status reveals 
smbd stopped
nmbd stopped
So, I decided I didn't like the current system configuration and reload 
RH7.1. Upon reload the daemons run fine. Change the /etc/samba/smb.conf 
file and smbadduser and smbpasswd and the thing breaks again.
I added to the /etc/rc.d/rc.local file
/usr/sbin/smbd -D
/usr/sbin/nmbd -D
and rebooted.
Same scenario. Is it just Friday the 13th or just the broken smb stack?