<type 'exceptions.AttributeError'>: 'FileLock' object has no attribute 'gettext'

Binary package hint: aptdaemon

crash on installing a software package from synaptic

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: aptdaemon 0.41+bzr645-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
Annotation: Applying software changes failed
Architecture: i386
Date: Sun Apr 17 16:22:46 2011
DesktopFile: /usr/share/aptdaemon/aptdaemon.desktop
ExecutablePath: /usr/sbin/aptd
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110330)
PackageArchitecture: all
SourcePackage: aptdaemon
Title: <type 'exceptions.AttributeError'>: 'FileLock' object has no attribute 'gettext'
TransactionDepends: [['java-common=0.40ubuntu1', 'odbcinst=2.2.14p2-2ubuntu1', 'sun-java6-bin=6.24-1build0.10.10.1', 'unixodbc=2.2.14p2-2ubuntu1', 'odbcinst1debian2=2.2.14p2-2ubuntu1', 'sun-java6-jre=6.24-1build0.10.10.1', 'gsfonts-x11=0.21'], [], [], [], [], [], []]
TransactionErrorCode: error-unknown
TransactionKwargs: {}
TransactionLocale: en_US.UTF8
TransactionOutput:

TransactionPackages: [[dbus.String(u'sun-java6-jdk'), dbus.String(u'openjdk-6-doc'), dbus.String(u'sun-java6-demo'), dbus.String(u'sun-java6-source')], [], [], [], [], []]
TransactionRole: role-commit-packages
UpgradeStatus: No upgrade log present (probably fresh install)