All this command does is write a macro that does

/focus <target>

So the <target> for this command can be any regular wow target, like party1, raid20, targettarget, toonname. The command does not use the special Jamba master target name.

This command has been removed in 0.5 and here is why:

In order to use the setfocus command, you

a) have to be out of combat.
b) have to press a key to actually set the focus on all your toons (the keybind setting is in your regular wow keybind menu).