We just started having the need to mount a Windows share to an AIX box
and ran into this problem.
Doing some searching in the group here and on the web It looks like
this topic has come up (in one form or another) over the past 5+
years, but many posts haven't either been answered or provided some
resolution that doesn't seem to work.

Goal:

Mount a windows share from a Windows Server 2003 (Win2k3) box that is
an AD Controller (Active Directory Controller) to an AIX 5300-05
server.

Problem:

When trying to mount with a correct domain user/password you receive
the error message:

There was an error connecting the share or the server.
Make sure the lsdev command shows that device nsmb0 is in
the Available state. Also make sure that the share name,
user name and password are accurate.

nsmb0 is active and we can mount Windows shares from WinXP boxes that
are not part of a domain.

Using a WinXP or Linux box we are able to mount the share from the
Win2k3 server.

Issue:

From testing and looking at other posts on this topic, it appears that
the bos.cifs_fs package can only work with a local user name on the
Windows box and not a Domain one.

Creating a local user on the Server is a work around, however presents
a problem for an AD Controller.
You can not create local user names on that type of box.

Those who have done tcpdumps have mentioned that no domain information
is being sent during the mount request and using -o
wrkgrp= is the way around this. This isn't working for
this scenario.

Our current cifs package release is:
bos.cifs_fs.rte 5.3.0.61 COMMITTED Runtime for SMBFS
bos.cifs_fs.smit 5.3.0.60 COMMITTED SMIT Interface for
SMBFS

I will try to do a ML update on the box including putting any later
updates to the cifs package.

But I'm curious if anybody else ever found a workaround or has
suggestions before submitting this to IBM.