<type 'exceptions.TypeError'>: 'dbus.Struct' object does not support item assignment

Binary package hint: aptdaemon

This bug occurred when I tried to install the latest Dropbox package in Natty. It is obtainable here:
https://www.dropbox.com/download?dl=packages/nautilus-dropbox_0.6.7_i386.deb

Installation failed and this report was generated. Sorry for the cryptic bug summary.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: aptdaemon 0.40+bzr541-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-1.28-generic 2.6.38-rc2
Uname: Linux 2.6.38-1-generic i686
NonfreeKernelModules: wl
Annotation: Installation of the package file failed
Architecture: i386
Date: Thu Feb 3 16:27:15 2011
DesktopFile: /usr/share/aptdaemon/aptdaemon.desktop
ExecutablePath: /usr/sbin/aptd
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110122)
PackageArchitecture: all
SourcePackage: aptdaemon
Title: <type 'exceptions.TypeError'>: 'dbus.Struct' object does not support item assignment
TransactionDepends: [[], [], [], [], [], [], []]
TransactionKwargs: {'path': dbus.String(u'/home/ingo/Downloads/nautilus-dropbox_0.6.7_i386.deb'), 'force': dbus.Boolean(False)}
TransactionLocale: en_US.UTF8
TransactionPackages: [[], [], [], [], [], []]
TransactionRole: role-install-file