ubuntu 11.04 crach while installing

[ghsghs]

i get massage while installing ubuntu telling me :

installing crach report to https://bugs.launchpad.net/ubuntu/+filebug?

to get info on this bug /var/log/syslog

i tried to reinstalling = same massage

[Ubuntu Foundations Team Bug Bot (crichton)]

Exception during installation:
Aug 12 21:53:47 ubuntu plugininstall.py: Traceback (most recent call last):
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1547, in <module>
Aug 12 21:53:47 ubuntu plugininstall.py: install.run()
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 56, in wrapper
Aug 12 21:53:47 ubuntu plugininstall.py: func(self)
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 208, in run
Aug 12 21:53:47 ubuntu plugininstall.py: self.remove_extras()
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 1303, in remove_extras
Aug 12 21:53:47 ubuntu plugininstall.py: self.do_remove(regular)
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/share/ubiquity/plugininstall.py", line 923, in do_remove
Aug 12 21:53:47 ubuntu plugininstall.py: if not cache.commit(fetchprogress, installprogress):
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/lib/python2.7/dist-packages/apt/deprecation.py", line 98, in deprecated_function
Aug 12 21:53:47 ubuntu plugininstall.py: return func(*args, **kwds)
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 433, in commit
Aug 12 21:53:47 ubuntu plugininstall.py: res = self._fetch_archives(fetcher, pm)
Aug 12 21:53:47 ubuntu plugininstall.py: File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 279, in _fetch_archives
Aug 12 21:53:47 ubuntu plugininstall.py: raise LockFailedException("Failed to lock %s" % lockfile)
Aug 12 21:53:47 ubuntu plugininstall.py: LockFailedException: Failed to lock /target/var/cache/apt/archives/lock
Aug 12 21:53:47 ubuntu plugininstall.py: