I am a little new to Centos & Samba but have been in the IT field for several years. I have read several posts on these forums as well as others over the past several weeks and have not been able to allow my Centos/Samba box to accept joining by an XP client. I get to the point where it asks for administrator with rights to join and its either password/username invalid or domain does not exist depending on which username/password combination I put in.

If anyone has ironclad way to fix this it would be greatly appreciated my me and others. I'm at a loss because i've tried everything and its still not working. HELP!!!

For me it depends on what users I have set up. Either it can be an administrator mapped to root, or it can be root directly if set up as a samba user.

Make sure you're backend is set correctly. I had that problem and i kept running sudo smbpasswd -a <<usrname>>

then i discovered that the backend was set to tdbsam, as soon as i set it to smbpasswd it worked perefectly.

Try that

-L