fai-setup conflict with 'chgrp'

[Peter Simko]

I'm only working on this FAI project for a few hours a week, so progress
is slow. Here's my latest problem (and thanks to Thomas Lange for
answering my last question):

When running make-fai-nfsroot or fai-setup I get the same error message.
dpkg: error processing /var/cache/apt/archives/file_utils-4.1_i386.deb
(--unpack):
  trying to overwrite '/bin/chgrp', which is also in package coreutils

While I try to figure out where to go from there, I have a more general
question: Since my install server also hosts a local debian mirror, how
do I specify a filesystem with FAI_DEBMIRROR in fai.conf?

Thanks,
Pete S.