[CentOS] AD Issues with Centos 4

I have the latest Centos (4.1), all YUM'd up to date.  I've been through
the How-TO's on Samba's site as well as 4 million other sites and still
can't get proper AD (Active Directory) Authentication to work.  It looks
like it's working, appears in the domain server list and pulls users and
groups.  If I do a klist -u, I see all the users with domain+username
correctly.  However, I can't apply any of that security to any
directories on the box or see those users with Webmin (when doing Samba
Share security).  The users who don't have local accounts can't browse
the samba server either (as soon as they connect, it pops up the login
ID & Pass)

I followed everything and have been working on the issue for 4 days.  Am
I missing something?  Please help!

Thanks.