>I did have a problem with patching qmail-smtpd (I got a warning about a
>return type, see earlier e-mail on list) but I'm not sure if that's the
>problem.
>/etc/shadow is owned by user/group root.
the roots of your (and 90% of other people's problems) are 2
a) either your qmail-smtpd is not able to call checkpassowrd (check perms)
b) your checkpassword is unable to authenticate you because of access rights.
QUICK TEST:
chmod a+rxs /bin/checkpassword
If it works now, then it's one of the 2 problems, think about it and find a
good solution for your OS.
Kris