samba - Jul 2004 - Native mode switch causing "chdir (/path) failed"

We just switched our Windows 2003 Active Directory domain into native
mode and are encountering a strange problem: (Samba 2.2.8a)

It seems that group membership is not being honored when attempting to
access a share.

The shared directory has permissions like so:

# file: is
# owner: root
# group: DOMAIN\Domain Admins
user::rwx
group::rwx
group:DOMAIN\Domain Admins:rwx
mask::rwx
other::r-x
default:user::rwx
default:group::rwx
default:group:DOMAIN\Domain Admins:rwx
default:mask::rwx
default:other::---

The share is set up like so:
[is$]
        comment = Information Systems Shared
        path = /samba/group/is
        valid users = @"DOMAIN\Domain Admins"
        read only = No

The error I get is:
[2004/07/23 19:53:20, 0] smbd/service.c:set_current_service(60)
  chdir (/samba/group/is) failed

The user I am trying to connect as is DOMAIN\mrr001 and:

# getent group "DOMAIN\Domain Admins"
DOMAIN\domain admins:x:10001: ... DOMAIN\mrr001 ...

The only change that occurred was the active directory change. This
configuration had been working fine till that point. If I change the
file permissions (chmod o+rwx) I am able to connect just fine.

Anyone have any thoughts on this? I have had to open my file permissions
all the way up for the time being...

Thanks,

-- 
Mark Roach <Mark@EruditeTech.com>
www.EruditeTech.com