Comment 6 for bug 613008

This error seems relevant (from syslog):

Aug 3 14:05:14 ubuntu python: Traceback (most recent call last):
Aug 3 14:05:14 ubuntu python: File "/usr/share/ubiquity/install.py", line 1809, in do_install
Aug 3 14:05:14 ubuntu python: if not cache.commit(acquireprogress, installprogress):
Aug 3 14:05:14 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/deprecation.py", line 98, in deprecated_function
Aug 3 14:05:14 ubuntu python: return func(*args, **kwds)
Aug 3 14:05:14 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 406, in commit
Aug 3 14:05:14 ubuntu python: res = self._fetch_archives(fetcher, pm)
Aug 3 14:05:14 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 279, in _fetch_archives
Aug 3 14:05:14 ubuntu python: return self._run_fetcher(fetcher)
Aug 3 14:05:14 ubuntu python: File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 261, in _run_fetcher
Aug 3 14:05:14 ubuntu python: raise FetchFailedException(err_msg)
Aug 3 14:05:14 ubuntu python: FetchFailedException: Failed to fetch cdrom:[Ubuntu 10.10 _Maverick Meerkat_ - Alpha i386 (20100803.1)]/pool/main/u/ubiquity/oem-config-gtk_2.3.3_all.deb Impossible de démonter le cédérom dans /cdrom/, il doit toujours être en cours d'utilisation.
Aug 3 14:05:14 ubuntu python: Failed to fetch cdrom:[Ubuntu 10.10 _Maverick Meerkat_ - Alpha i386 (20100803.1)]/pool/main/u/ubiquity/oem-config_2.3.3_all.deb Impossible de démonter le cédérom dans /cdrom/, il doit toujours être en cours d'utilisation.

In my successful install I did not have this error message, but it could be that it fetched oem-config from the network.