I am using ubuntu 12 i am unable to install software from unix or from linux i am getting following error

reiki@reiki ~ $ sudo apt-get install preload

[sudo] password for reiki: 

Reading package lists... Done

Building dependency tree       

Reading state information... Done

The following NEW packages will be installed:

  preload

0 upgraded, 1 newly installed, 0 to remove and 21 not upgraded.

1 not fully installed or removed.

Need to get 35.6 kB of archives.

After this operation, 138 kB of additional disk space will be used.

Get:1 http://archive.ubuntu.com/ubuntu/ quantal/universe preload i386 0.6.4-2 [35.6 kB]

Fetched 35.6 kB in 1s (34.8 kB/s)

Selecting previously unselected package preload.

(Reading database ... 262032 files and directories currently installed.)

Unpacking preload (from .../preload_0.6.4-2_i386.deb) ...

Processing triggers for man-db ...

Processing triggers for ureadahead ...

ureadahead will be reprofiled on next reboot

Setting up opera (12.15.1748-1linuxmint) ...

ERROR:root:DebFileApplication import

Traceback (most recent call last):

  File "/usr/share/software-center/softwarecenter/db/__init__.py", line 4, in <module>

    from debfile import DebFileApplication, DebFileOpenError

  File "/usr/share/software-center/softwarecenter/db/debfile.py", line 25, in <module>

    from softwarecenter.db.application import Application, AppDetails

  File "/usr/share/software-center/softwarecenter/db/application.py", line 27, in <module>

    import softwarecenter.distro

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 197, in <module>

    distro_instance = _get_distro()

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 172, in _get_distro

    module = __import__(distro_module_name, globals(), locals(), [], -1)

ImportError: No module named linuxmint

Traceback (most recent call last):

  File "/usr/sbin/update-software-center", line 38, in <module>

    from softwarecenter.db.update import rebuild_database

  File "/usr/share/software-center/softwarecenter/db/update.py", line 33, in <module>

    from softwarecenter.backend.scagent import SoftwareCenterAgent

  File "/usr/share/software-center/softwarecenter/backend/scagent.py", line 28, in <module>

    from softwarecenter.distro import get_distro, get_current_arch

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 197, in <module>

    distro_instance = _get_distro()

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 172, in _get_distro

    module = __import__(distro_module_name, globals(), locals(), [], -1)

ImportError: No module named linuxmint

dpkg: error processing opera (--configure):

 subprocess installed post-installation script returned error exit status 1

Setting up preload (0.6.4-2) ...

 * Starting Adaptive readahead daemon preload                            [ OK ] 

Processing triggers for menu ...

Processing triggers for ureadahead ...

Errors were encountered while processing:

 opera

E: Sub-process /usr/bin/dpkg returned an error code (1)

reiki@reiki ~ $ 

When i try to remove opera then i got following error

Reading package lists... Done

Building dependency tree       

Reading state information... Done

The following packages will be REMOVED:

  opera

0 upgraded, 0 newly installed, 1 to remove and 21 not upgraded.

1 not fully installed or removed.

After this operation, 45.0 MB disk space will be freed.

Do you want to continue [Y/n]? y

(Reading database ... 261623 files and directories currently installed.)

Removing opera ...

ERROR:root:DebFileApplication import

Traceback (most recent call last):

  File "/usr/share/software-center/softwarecenter/db/__init__.py", line 4, in <module>

    from debfile import DebFileApplication, DebFileOpenError

  File "/usr/share/software-center/softwarecenter/db/debfile.py", line 25, in <module>

    from softwarecenter.db.application import Application, AppDetails

  File "/usr/share/software-center/softwarecenter/db/application.py", line 27, in <module>

    import softwarecenter.distro

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 197, in <module>

    distro_instance = _get_distro()

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 172, in _get_distro

    module = __import__(distro_module_name, globals(), locals(), [], -1)

ImportError: No module named linuxmint

Traceback (most recent call last):

  File "/usr/sbin/update-software-center", line 38, in <module>

    from softwarecenter.db.update import rebuild_database

  File "/usr/share/software-center/softwarecenter/db/update.py", line 33, in <module>

    from softwarecenter.backend.scagent import SoftwareCenterAgent

  File "/usr/share/software-center/softwarecenter/backend/scagent.py", line 28, in <module>

    from softwarecenter.distro import get_distro, get_current_arch

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 197, in <module>

    distro_instance = _get_distro()

  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 172, in _get_distro

    module = __import__(distro_module_name, globals(), locals(), [], -1)

ImportError: No module named linuxmint

dpkg: error processing opera (--remove):

 subprocess installed post-removal script returned error exit status 1

No apport report written because MaxReports is reached already

                                                              Processing triggers for menu ...

Errors were encountered while processing:

 opera

E: Sub-process /usr/bin/dpkg returned an error code (1)

now i am unable to remove opera