package fai-nfsroot (not installed) failed to install/upgrade: subprocess new pre-installation script returned error exit status 1

[Thom Yorke]

ERROR: The package fai-nfsroot can only be installed inside the nfsroot.
dpkg: error processing archive /var/cache/apt/archives/fai-nfsroot_5.3.2-0~6669~ubuntu16.04.1_all.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
Processing triggers for man-db (2.7.5-1) ...
Errors were encountered while processing:
 /var/cache/apt/archives/fai-nfsroot_5.3.2-0~6669~ubuntu16.04.1_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: fai-nfsroot (not installed)
ProcVersionSignature: Ubuntu 4.8.0-49.52~16.04.1-generic 4.8.17
Uname: Linux 4.8.0-49-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
Date: Fri May 5 22:55:36 2017
DuplicateSignature:
 package:fai-nfsroot:(not installed)
 Preparing to unpack .../fai-nfsroot_5.0.3ubuntu1_all.deb ...
 ERROR: The package fai-nfsroot can only be installed inside the nfsroot.
 dpkg: error processing archive /var/cache/apt/archives/fai-nfsroot_5.0.3ubuntu1_all.deb (--unpack):
  subprocess new pre-installation script returned error exit status 1
ErrorMessage: subprocess new pre-installation script returned error exit status 1
InstallationDate: Installed on 2017-04-24 (11 days ago)
InstallationMedia:

RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.19
SourcePackage: fai
Title: package fai-nfsroot (not installed) failed to install/upgrade: subprocess new pre-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)