OK now making progress... Major thankyou's to
Chapter 8. Updating Samba-3
I can now join machines plus log in... Trying to reconstruct my errors:
I guess for starters, the smb.conf example file from the "unix and windows accounts in Zimbra ldap and zimbra admin ui 6" how-to is set up for ubuntu, and the create machine section doesn't work with centos/redhat - however, you can copy in the section from the original centos smb.conf, and that works - HOWEVER
I didn't discover that until I had installed a 2nd samba server, (my first one was just on a temp machine just for testing), and that SCREWED UP my SIDs... (this is an easy trap since it "sorta works", no errors, and users/groups work just fine -maybe since the SID is also stored on the zimbra ldap server..) so I figured - hey, zimbra likes the new server just the same as the original one...! but a quick "net getlocalsid MY-DOMAIN" will set you straight - you need to do the command for both the Workgroup, AND the netbios name (smb.conf). Mine didn't match- one was the old sid and one the new one.
The great help from SMB's website got it working MUCH BETTER NOW.
I'm not sure if I'll find any other problems, but I'll start testing workstations now...
PS. If you're fighting a technical (or other problem), remember to ask our heavenly Father for help- After all the difficulties Iv'e had with this, I finally just stopped and prayed for guidance - I can't say how, but almost immediately I just typed in a url that linked me to the above smb page, and it directly took me to the solution. God knows about tech stuff -- AND cares enough to help!
Peace