The command gets executed anyway, right? There's an easy fix. Make a
backup copy of your "/etc/hosts" file, and then edit (via sudo gedit)
"/etc/hosts".

Look for a line that contains:

127.0.1.1 LinuxBox3.something

where "something" is likely the workgroup name you entered somewhere.
(On my computer, it was the second line in /etc/hosts.) Get rid of
the ".something" (be sure to delete the "."), so the line reads

127.0.1.1 LinuxBox3

save the file, and reboot.

I'll try that (I'm presently on work XP system). Yes the
command gets executed anyway. I don't remember entering a workgroup
name when I loaded Ubuntu. It did ask me for a domain name, and I
made something up because I don't run a domain. Maybe that's the
problem.