I'm no longer sure which bug-report this is.But,I did manage to fix
several issues with the Unity-Desktop via 'Compiz-Manager'.Look this
up in Ubuntu-Software.It seems to have good reviews,overall.For those
of you whose command-line skills are not that good,like mine; it
solved the Unity troubles,by deselecting this feature of 11.04
automatically! (Note: had previously selected "Ubuntu-Classic",at
bottom of screen,upon login.)Even this didn't seem to completely solve
problems with 11.04,though.It was only on install of Compiz-Manger
utillity,that 11.04 seemed to work smoothly again.
(It offers a graphical-interface for those who aren't very familar
with Terminal-commands or problem-solving via that route.Beyond that,I
know nothing;just that it worked for me.)You can also do an online
search: Fix Ubuntu 11.04.(Also did that.Helped in leading me to this
possible solution.  John.

On 5/23/11, mimo titolindo <email address hidden> wrote:
> close this question, I have solved...
>
> On Mon, May 23, 2011 at 8:49 AM, Brian Murray <email address hidden> wrote:
>
>> ** Tags added: verification-done
>>
>> --
>> You received this bug notification because you are a direct subscriber
>> of a duplicate bug (704271).
>> https://bugs.launchpad.net/bugs/659438
>>
>> Title:
>>  Installation/Removal fails because of package which could not be
>>  located (failure in apt.Cache.required_download)
>>
>> Status in Aptdaemon:
>>  In Progress
>> Status in “apt” package in Ubuntu:
>>  Triaged
>> Status in “aptdaemon” package in Ubuntu:
>>  In Progress
>> Status in “python-apt” package in Ubuntu:
>>  Invalid
>> Status in “apt” source package in Maverick:
>>  New
>> Status in “aptdaemon” source package in Maverick:
>>  In Progress
>> Status in “python-apt” source package in Maverick:
>>  Invalid
>>
>> Bug description:
>>  Steps to reproduce:
>>
>>  1. Run apt-get nstall ms-ttcorefonts-installer in a terminal
>>  2. Close the terminal window at the EULA question (apt-get/dpkg/debconf)
>> will sting hang in the background and lock the system)
>>  3. Reboot
>>
>>
>>  Traceback (most recent call last):
>>    File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 768,
>> in simulate
>>      return self._simulate_helper(trans, status_path)
>>    File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 936,
>> in _simulate_helper
>>      return depends, status, self._cache.required_download, \
>>    File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 218, in
>> required_download
>>      pm.get_archives(fetcher, self._list, self._records)
>>  SystemError: E:I wasn't able to locate file for the liblua50 package.
>> This
>> might mean you need to manually fix this package.
>>
>> To unsubscribe from this bug, go to:
>> https://bugs.launchpad.net/aptdaemon/+bug/659438/+subscribe
>>
>
> --
> You received this bug notification because you are a direct subscriber
> of a duplicate bug (764335).
> https://bugs.launchpad.net/bugs/659438
>
> Title:
>   Installation/Removal fails because of package which could not be
>   located (failure in apt.Cache.required_download)
>
> Status in Aptdaemon:
>   In Progress
> Status in “apt” package in Ubuntu:
>   Triaged
> Status in “aptdaemon” package in Ubuntu:
>   In Progress
> Status in “python-apt” package in Ubuntu:
>   Invalid
> Status in “apt” source package in Maverick:
>   New
> Status in “aptdaemon” source package in Maverick:
>   In Progress
> Status in “python-apt” source package in Maverick:
>   Invalid
>
> Bug description:
>   Steps to reproduce:
>
>   1. Run apt-get nstall ms-ttcorefonts-installer in a terminal
>   2. Close the terminal window at the EULA question (apt-get/dpkg/debconf)
> will sting hang in the background and lock the system)
>   3. Reboot
>
>
>   Traceback (most recent call last):
>     File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 768,
> in simulate
>       return self._simulate_helper(trans, status_path)
>     File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 936,
> in _simulate_helper
>       return depends, status, self._cache.required_download, \
>     File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 218, in
> required_download
>       pm.get_archives(fetcher, self._list, self._records)
>   SystemError: E:I wasn't able to locate file for the liblua50 package. This
> might mean you need to manually fix this package.
>
> To unsubscribe from this bug, go to:
> https://bugs.launchpad.net/aptdaemon/+bug/659438/+subscribe
>