Installer crashes during install from hard disk

[Dan Douglas]

Binary package hint: ubiquity

Installing ubuntu 11.04 (Edubuntu) to HDD. Disk setup
dev/sda
  - sda1 FAT 5 GB - Install image here, created on on another Ubuntu box from *.iso file
  - sda2 ext4 73 GB - set to mount as /, already formatted
  - sda3 swap 2 GB

Ran gpartd and made sure no partitions were locked
umount /cdrom from terminal before running installer

Gets past disk selection, keyboard and timezone. Then "Installer crashed" dialog pops up.

[Dave Gilbert (ubuntu-treblig)]

From syslog:
May 21 17:17:49 ubuntu install.py: Exception during installation:
May 21 17:17:49 ubuntu install.py: Traceback (most recent call last):
May 21 17:17:49 ubuntu install.py: File "/usr/share/ubiquity/install.py", line 610, in <module>
May 21 17:17:49 ubuntu install.py: install.run()
May 21 17:17:49 ubuntu install.py: File "/usr/share/ubiquity/install.py", line 124, in run
May 21 17:17:49 ubuntu install.py: self.copy_all()
May 21 17:17:49 ubuntu install.py: File "/usr/share/ubiquity/install.py", line 301, in copy_all
May 21 17:17:49 ubuntu install.py: assert os.path.exists(fs_size), "Missing filesystem.size."
May 21 17:17:49 ubuntu install.py: AssertionError: Missing filesystem.size.