I'm not very experienced with unix, so I would appreciate any help in
this problem solving...

Playing with unix box (NetBSD 1.2) for learning I run 'vipw' from a
remote WinNT machine via telnet session. At that moment the NT displayed
me a 'blue screen of dead'. After restarting NT I telnet again and
discovered that the previous telnet session is still active and the
system didn't abort it as well as shell and vipw. Well, I killed it with
'kill -9' command, and checked the /etc/master.passwd - it was OK. I run
vipw again and got:

vipw: the passwd file is busy

As I understand it concerns /usr/bin/passwd file, which is now locked.

Q: What happened, how to unlock the /usr/bin/passwd and what to do in
situations like this one?

Igor.