[apport] ubiquity crashed with AttributeError in on_back_clicked()

Binary package hint: ubiquity

Running the Install ISO for Feisty Herd 3
In the partitioner in ubiquity I clicked on manually edit, and next, then I clicked back, and it crashed.

ProblemType: Crash
Date: Sun Feb 4 23:32:02 2007
DistroRelease: Ubuntu 7.04
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InterpreterPath: /rofs/usr/bin/python2.5
Package: ubiquity 1.3.17
ProcCmdline: /usr/bin/python /usr/lib/ubiquity/bin/ubiquity gtkui
ProcCwd: /home/ubuntu
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/lib/ubiquity/bin/ubiquity', 'gtkui']
SourcePackage: ubiquity
Traceback:
 Traceback (most recent call last):
   File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 1253, in on_back_clicked
     if self.gparted_subp is not None:
 AttributeError: Wizard instance has no attribute 'gparted_subp'
Uname: Linux ubuntu 2.6.20-6-generic #2 SMP Wed Jan 31 20:53:39 UTC 2007 i686 GNU/Linux