ubiquity-dm crashed with ValueError in command(): invalid literal for int() with base 10: ''

Binary package hint: ubiquity

Ubuntu 11.04 CD-image installer crashed while upgrading from 10.04 LTS. As a result it reverted to LiveCD trial mode

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: ubiquity 2.6.10
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
Architecture: i386
Date: Mon May 2 15:05:05 2011
ExecutablePath: /usr/bin/ubiquity-dm
InterpreterPath: /usr/bin/python2.7
LiveMediaBuild: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcCmdline: /usr/bin/python /usr/bin/ubiquity-dm vt7 :0 hostname /usr/bin/ubiquity --greeter --only
ProcEnviron:
 LANGUAGE=
 PATH=(custom, no user)
 LANG=en_US.UTF-8
PythonArgs: ['/usr/bin/ubiquity-dm', 'vt7', ':0', 'hostname', '/usr/bin/ubiquity', '--greeter', '--only']
SourcePackage: ubiquity
Title: ubiquity-dm crashed with ValueError in command(): invalid literal for int() with base 10: ''
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: