Error Message: tree connect failed

[Jonathan Lee]

I set my Samba Server 2.0.5a as Domain Server,and named it as BEEP (I'm
using Redhat 6.0)
My Samba Server is named as FileServer1.
The following the my smb.conf:
[global]
    workgroup = BEEP
    security = yes
    log file = /var/log/samba/log.%m
    max log size = 50
    name resolve order = wins host lmhosts bcast
    socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
    domain logons = yes
    os level = 65
    preferred master = yes
    domain master = yes
    dns proxy = no
    wins server = 90.0.254.2
[netlogon]
    path=/home/netlogon
    writeable=no
    guest ok = no
[homes]
    read only = no
    browseable = no


When I try the following command "smbclient -L FileServer1 -U root -W BEEP",
it ask me for the password, I give the correct password, it runs OK.
But when I change a user (which is an account on Linux box), I get the
following message:
"tree connect failed: ERRSRV -ERRinventname (Invalid network name in tree
connect.)"

I do not think it's due to bad password, since when I type wrong password,
the message told me the password is wrong.
So, I think the Samba Server already think that user is a valid user.

Also, the following test passed OK.
I use that account named as "jonathan", and run the following command:
$smbclient "\\\\FileServer1\\jonathan" -U jonathan -W BEEP
When I give the correct password, it runs OK.

So, please tell me why I'm failed and get the error message of "tree connect
failed"