Comment 5 for bug 107178

Could somebody affected by this please start the installer with 'ubiquity --debug' from a terminal window, and when the problem occurs make sure to quit the installer (to ensure that all log messages are flushed) and attach /var/log/installer/debug, /var/log/syslog, and /var/log/partman to this bug?

Something is definitely crazily wrong, but I can't see what it is so far. The debug output ought to help.