My freebsd hosted build is failing during the creation of base.tgz 
[but that doesn't stop the build - directly]
The error is:

Creating base.tgz
nbpax: unknown group `floppy'
nbpax: failed at line 1169 of the specification

sure enough that line says:

./usr/sbin/postdrop type=file uname=root gname=floppy mode=02555 time=1084490986.0 sha1=a02d64d0ecfb0cf4a51011261a1838701919009d

there is no group floppy mentioned  in/under any of
src/etc/group 
src/etc/mtree/
src/distrib/sets/  

However, there is a group floppy:*:11: in the host's
/etc/group, in src/etc/group 11 is maildrop, and sure enough maildrop
is the group inteneded for postdrop.

I can't quite see the link between the two, but I'd guess that
maketars is running somestep using without specifying $etcdir.
I did an unpriv'd build the actual ownership of postdrop in my destdir
is totally unrelated, and the METALOG has the correct info
gname=maildrop.

Clue anyone?

Thanks
--sjg