Some distributions, like Caldera, start UIDs at 100, others, like Red Hat, at 500, and still others, like Debian, at 1000 for non-privileged users. Just decide on a scheme and stick to it. Since each distribution does its own thing, in order to mix distributions within an organization, you have to intervene manually if the systems are networked. Contrary to popular belief, the UID field does not have to be unique. Then create another entry, perhaps tuber, with a UID of 0.
Some systems require the root entry to exist and be the first entry.
But root's password has been locked with an invalid entry. At this point, your choices are to telnet in and kill the screen-lock process or to reboot the machine. The other possibility for getting out is to use an unlocked virtual terminal if you have one running to which you can switch. Before I leave UIDs, here are two more things to think about. These files can cause many problems and probably should not be used.