Comment 2 for bug 770235

Thanks for your report.

Here is the error from the logs:
Apr 25 11:17:48 ubuntu python: log-output -t ubiquity umount -f /target/proc
Apr 25 11:17:48 ubuntu python: log-output -t ubiquity umount -f /target/sys
Apr 25 11:17:48 ubuntu python: log-output -t ubiquity umount -f /target/dev
Apr 25 11:17:48 ubuntu python: log-output -t ubiquity chroot /target mount -t proc proc /proc
Apr 25 11:17:48 ubuntu python: log-output -t ubiquity chroot /target mount -t sysfs sysfs /sys
Apr 25 11:17:48 ubuntu python: log-output -t ubiquity mount --bind /dev /target/dev
Apr 25 11:17:49 ubuntu python: Traceback (most recent call last):
Apr 25 11:17:49 ubuntu python: File "/usr/lib/ubiquity/ubiquity/install_misc.py", line 739, in do_install
Apr 25 11:17:49 ubuntu python: if not cache.commit(fetchprogress, installprogress):
Apr 25 11:17:49 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/deprecation.py", line 98, in deprecated_function
Apr 25 11:17:49 ubuntu python: return func(*args, **kwds)
Apr 25 11:17:49 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 424, in commit
Apr 25 11:17:49 ubuntu python: res = self._fetch_archives(fetcher, pm)
Apr 25 11:17:49 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 271, in _fetch_archives
Apr 25 11:17:49 ubuntu python: raise LockFailedException("Failed to lock %s" % lockfile)
Apr 25 11:17:49 ubuntu python: LockFailedException: Failed to lock /target/var/cache/apt/archives/lock