[Samba] diagnosing cause of NT_STATUS_BAD_NETWORK_NAME error

[Walter H. Whitlock]

I'm trying to find out why I am unable to access public shares on host
mythbe (from host mythbe) due to a NT_STATUS_BAD_NETWORK_NAME error.
I am able to access home shares.  I've checked all of the host setup
issues I know about (smb.conf, directory permissions, iptables,
selinux) but I don't see any problems.  Can anyone spot a problem or
suggest where I could investigate?  Below is some information given by
command lines run on host mythbe:

=======run as root
>>uname -r
2.6.18-53.1.14.el5.centos.plus

=======run as root, press ENTER at Password: prompt
>>smbclient //mythbe/tmp
Anonymous login successful
tree connect failed: NT_STATUS_BAD_NETWORK_NAME

=======run as root, enter walter's password at Password: prompt
>>smbclient //mythbe/walter
smb: \> exit

=======run as root
>>testparm -s
[global]
       workgroup = WHITLOCK NET
       server string = Samba Server Version %v
       map to guest = Bad User
       passdb backend = tdbsam
       guest account = ftp
       username map = /etc/samba/smbusers
       log level = 3
       acl compatibility = winnt
       server signing = auto
       preferred master = No
       domain master = No
       dns proxy = No
       ldap ssl = no
       cups options = raw

[homes]
       comment = Home Directories
       read only = No
       browseable = No

[tmp]
       comment = test share
       path = /tmp
       guest ok = Yes
       case sensitive = No
       strict locking = No
       msdfs proxy = no

=======run as root, press ENTER at Password: prompt
>>smbclient -L //mythbe
Anonymous login successful

       Sharename       Type      Comment
       ---------       ----      -------
       tmp             Disk      test share
       IPC$            IPC       IPC Service (Samba Server Version 
3.0.25b-1.el5_1.4)
Anonymous login successful

       Server               Comment
       ---------            -------
       HOSTA                Hosta
       MYTHBE               Samba Server Version 3.0.25b-1.el5_1.4

       Workgroup            Master
       ---------            -------
       WHITLOCK NET         HOSTA

=======run as root
>>ls -ld /tmp
drwxrwxrwt 12 root root 4096 Apr 15 08:39 /tmp

=======run as root
>>/sbin/iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

=======run as root
>>dmesg|grep -i selinux
SELinux:  Initializing.
SELinux:  Starting in permissive mode
selinux_register_security:  Registering secondary module capability
SELinux:  Registering netfilter hooks
SELinux:  Disabled at runtime.
SELinux:  Unregistering netfilter hooks
audit(1208262956.298:2): selinux=0 auid=4294967295