What's wrong with this net use command?

You might have to specify explicitly that you want to reference the user account on the remote system, otherwise, Windows might try to establish the connection referencing your local Administrator account.

To do this, supply the domain (in this case the name of the remote computer) with the /user: parameter:

net use X: \\Samba_Server\gis /user:Samba_Server\Administrator <admin-pwd> /persistent:yes

The syntax command that you have entered is correct. Error 1326 is a common error number used to denote authentication failures on Windows system. These failures are usually related, but not limited to:

  1. account does not exist
  2. guest account needs to be enabled
  3. auto-logon and blank password is enabled on remote computer
  4. folder or drive permissions shared on the remote computer

In your case, if you have checked that the account you are using exists on the remote computer(1), the problem might be caused by point 3. SAMBA shares has a configuration option when turned on would exhibit this behavior on Windows clients.

guest only = yes

More information on this option can be found http://www.samba.org/samba/docs/man/manpages-3/smb.conf.5.html#GUESTONLY