installing precise crashes 'scanning disks'

ubuntu-bug data collection, ref bug 927463
Can reproduce on every reboot with the usbkey.

key was created with the alpha-2 CD iso: precise-desktop-i386.iso

Interestingly; I did notice that if I manually run the installer again, after being dropped back to a try-ubuntu desktop, it works and scans the drives successfully.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: ubiquity 2.9.15
ProcVersionSignature: Ubuntu 3.2.0-12.21-generic-pae 3.2.2
Uname: Linux 3.2.0-12-generic-pae i686
ApportVersion: 1.91-0ubuntu1
Architecture: i386
CasperVersion: 1.303
Date: Fri Feb 10 05:54:45 2012
LiveMediaBuild: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20120201.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)