E: The package adobe-flashplugin needs to be reinstalled, but I can't find an archive for it. E: Internal error opening cache (1). Please report.

See here: http://ubuntuforums.org/showthread.php?t=1305829&page=3

Please Please Please Please DO NOT EVER install this stupid package, it causes all manner of hell like this. Tell everybody you know to avoid this thing like Paris Hilton avoids talent. I have seen this exact question literally HUNDREDS of times on here :(

To install flash you need flashplugin-nonfree, it even specifys it on:
https://help.ubuntu.com/community/RestrictedFormats/Flash

sudo rm /var/lib/dpkg/info/adobe-flashplugin.prerm; sudo dpkg-reconfigure adobe-flashplugin --force; sudo dpkg --purge --force-all adobe-flashplugin

Should fix it. Tell the world that adobe-flashplugin is the DEVIL

This also has been solved here:
http://ubuntuforums.org/archive/index.php/t-1285455.html

May add further steps but I copied the commands given to work.

or use gnash for flash, it works.

> avoid this thing like Paris Hilton avoids talent
^ROFL^
> exact question literally HUNDREDS of times
confirm

My 2 cents.
https://answers.launchpad.net/ubuntu/+source/update-manager/+question/88628

yeah people posting questions like the one yuo posted. The flash part of the restricted extras states clearly to use flashplugin-nonfree or use the 64bit ppa to get native 64bit flash.

Thanks zvacet, that solved my question.

Thanks n cudos to u zvacet a million tyms again.