ubiquity hangs when trying to install from live session

[sudodus]

this is bug 1299473, but launchpad did not find it, even when I supplied exactly the same title.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubiquity 2.17.10
ProcVersionSignature: Ubuntu 3.13.0-20.42-generic 3.13.7
Uname: Linux 3.13.0-20-generic x86_64
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
CasperVersion: 1.339
CurrentDesktop: XFCE
Date: Tue Apr 1 08:07:53 2014
InstallCmdLine: file=/cdrom/preseed/mythbuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- debian-installer/language=sv keyboard-configuration/layoutcode?=se
LiveMediaBuild: Mythbuntu 14.04 LTS "Trusty Tahr" - Daily amd64 (20140331)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=sv_SE.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)