ubiquity crashed with TypeError in __new__(): object of type 'NoneType' has no len()

Description: Ubuntu oneiric (development branch)
Release: 11.10
ubiquity:
  Installed: 2.7.24
  Candidate: 2.7.24
  Version table:
 *** 2.7.24 0
        500 http://archive.ubuntu.com/ubuntu/ oneiric/main i386 Packages
        100 /var/lib/dpkg/status
Expected Outcome: There should be no error reported.
Actual Outcome: An error was reported when switching between "I don't want to connect to a wi-fi network right now" and "Connect to this network".

NOTE: There is no /var/log/partman file available as I had not reached the Partitioning Part of the Installation Setup yet.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: ubiquity 2.7.24
ProcVersionSignature: Ubuntu 3.0.0-9.15-generic 3.0.3
Uname: Linux 3.0.0-9-generic i686
Architecture: i386
CasperVersion: 1.280
Date: Wed Aug 31 12:14:16 2011
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InterpreterPath: /usr/bin/python2.7
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Beta i386 (20110831)
ProcCmdline: /usr/bin/python /usr/lib/ubiquity/bin/ubiquity gtk_ui
ProcEnviron: Error: [Errno 13] Permission denied: '/proc/6823/environ'
PythonArgs: ['/usr/lib/ubiquity/bin/ubiquity', 'gtk_ui']
SourcePackage: ubiquity
Title: ubiquity crashed with TypeError in __new__(): object of type 'NoneType' has no len()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: