ubiquity crashed with TypeError: cell_data_func() takes exactly 4 arguments (5 given)

[Peter Thor]

Trying amd64 iso, upon install using erasing complete disk the install process crashes after entering user name/pw and pressing forward.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: ubiquity 2.7.20
ProcVersionSignature: Ubuntu 3.0.0-9.14-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
Architecture: amd64
CasperVersion: 1.280
Date: Tue Aug 30 18:01:59 2011
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InterpreterPath: /usr/bin/python2.7
LiveMediaBuild: Lubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110830.1)
ProcCmdline: /usr/bin/python /usr/lib/ubiquity/bin/ubiquity gtk_ui
ProcEnviron: Error: [Errno 13] Permission denied: '/proc/3942/environ'
PythonArgs: ['/usr/lib/ubiquity/bin/ubiquity', 'gtk_ui']
SourcePackage: ubiquity
Title: ubiquity crashed with TypeError: cell_data_func() takes exactly 4 arguments (5 given)
Traceback: TypeError: cell_data_func() takes exactly 4 arguments (5 given)
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: