ubiquity crashed with IndexError in render_slider()

[Hugo Melo]

Binary package hint: ubiquity

Used karmic alpha 4 to install ubuntu. Booted, connected to my wireless network and ran the installer.
I got the error message after I chose us_intl and clicked forward. At that time It started the partitioner and didn't close the installer.. All the panels went fine and I could install ubuntu.
PS: I cannot click by tapping my touchpad. It just works pressing the buttons, but does nothing with tapping.

ProblemType: Crash
Architecture: amd64
Date: Fri Aug 28 18:35:12 2009
DistroRelease: Ubuntu 9.10
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InterpreterPath: /usr/bin/python2.6
LiveMediaBuild: Ubuntu 9.10 "Karmic Koala" - Alpha amd64 (20090812.3)
Package: ubiquity 1.99.6
ProcCmdline: /usr/bin/python /usr/lib/ubiquity/bin/ubiquity gtk_ui
ProcEnviron: Error: [Errno 13] Permission denied: '/proc/4286/environ'
ProcVersionSignature: Ubuntu 2.6.31-5.24-generic
PythonArgs: ['/usr/lib/ubiquity/bin/ubiquity', 'gtk_ui']
SourcePackage: ubiquity
Title: ubiquity crashed with IndexError in render_slider()
Uname: Linux 2.6.31-5-generic x86_64
UserGroups:

[Hugo Melo (hugo-melo)]

How can it be a duplicate of #386388?
This error appeared to me when I had started configuring the first panels. How can this bug happen when it tries to install grub?