ubiquity crashed with DBusException in call_blocking(): org.freedesktop.DBus.Error.ServiceUnknown: The name :1.70 was not provided by any .service files

Trying to install Ubuntu 11.10 (x64 PC) from Daily build (Dated 24 Aug 2011). Used UNetbootin v5.49 to copy to flash disk. Selected the Try Ubuntu first boot option. Once desktop was visible, clicked 'Install Ubuntu 11.10' icon on desktop. Selected English as install language, passed checks (4.6 GB space, plugged in to power, is connected to the internet). Selected 'Download updates while installing' and 'Install third-party software' check boxes and clicked on the 'Continue' button. Then started getting all these errors. Trying to install on Sony VAIO VGN-FW27GU laptop. See also Bug #833402 that I get as well.

Deselecting 'Install third-party software' seems to let me get further?

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: ubiquity 2.7.15
ProcVersionSignature: Ubuntu 3.0.0-9.14-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
Architecture: amd64
CasperVersion: 1.279
Date: Wed Aug 24 22:18:20 2011
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InterpreterPath: /usr/bin/python2.7
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110824)
ProcCmdline: /usr/bin/python /usr/lib/ubiquity/bin/ubiquity gtk_ui
ProcEnviron: Error: [Errno 13] Permission denied: '/proc/13400/environ'
PythonArgs: ['/usr/lib/ubiquity/bin/ubiquity', 'gtk_ui']
SourcePackage: ubiquity
Title: ubiquity crashed with DBusException in call_blocking(): org.freedesktop.DBus.Error.ServiceUnknown: The name :1.70 was not provided by any .service files
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: