package lrzsz 0.12.21-5 failed to install/upgrade: unable to create `/usr/bin/rz.dpkg-new' (while processing `./usr/bin/rz'): Read-only file system

[Raubvogel]

Was trying to install openssh-server and then got a crash report

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: lrzsz 0.12.21-5
ProcVersionSignature: Ubuntu 3.2.0-32.51-generic 3.2.30
Uname: Linux 3.2.0-32-generic x86_64
ApportVersion: 2.0.1-0ubuntu14
AptOrdering:
 lrzsz: Install
 minicom: Install
 lrzsz: Configure
 minicom: Configure
Architecture: amd64
Date: Sat Oct 20 19:18:36 2012
DpkgTerminalLog:
 Unpacking lrzsz (from .../lrzsz_0.12.21-5_amd64.deb) ...
 dpkg: error processing /var/cache/apt/archives/lrzsz_0.12.21-5_amd64.deb (--unpack):
  unable to create `/usr/bin/rz.dpkg-new' (while processing `./usr/bin/rz'): Read-only file system
DuplicateSignature:
 Unpacking lrzsz (from .../lrzsz_0.12.21-5_amd64.deb) ...
 dpkg: error processing /var/cache/apt/archives/lrzsz_0.12.21-5_amd64.deb (--unpack):
  unable to create `/usr/bin/rz.dpkg-new' (while processing `./usr/bin/rz'): Read-only file system
ErrorMessage: unable to create `/usr/bin/rz.dpkg-new' (while processing `./usr/bin/rz'): Read-only file system
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120822.4)
SourcePackage: lrzsz
Title: package lrzsz 0.12.21-5 failed to install/upgrade: unable to create `/usr/bin/rz.dpkg-new' (while processing `./usr/bin/rz'): Read-only file system
UpgradeStatus: No upgrade log present (probably fresh install)