[Samba] help with Samba v. 3.0.21b authentication

[Vahid Moghaddasi]

Hi All,
I have this strange problem that if the user has the same username in
UNIX as in Windows, he can do "net view \\server <file://server/>" with no
problem but
for users whose username is not the same
on UNIX as it is in Windows, "net view \\server <file://server/>" returns:
System error 5 has occurred.
Access is denied
and if try to map a share, I see the following in the log.winbindd:
[2006/02/07 15:38:00, 3]
nsswitch/winbindd_user.c:winbindd_getpwnam(336)
  [    0]: getpwnam WINTESTUSER
[2006/02/07 15:38:00, 5]
nsswitch/winbindd_user.c:getpwsid_sid2uid_recv(264)
  Could not query user's DOMAIN\wintestuser uid
[2006/02/07 15:46:04, 3]
nsswitch/winbindd_misc.c:winbindd_interface_version(454)

The user 'wintestuser' does not exist in unix. This is on Solaris 10
and Samba 3.0.21b, I am not using PAM for samba, not sure if that
causes this problem. Other Samba servers with lower version (3.04) do
not have this problem.
Thanks for any help.
Vahid.