Package is in a very bad inconsistent state - you should reinstall it before attempting a removal.There were a few others too who had similar problems on Ubuntu forums and this solution finally worked for me: remove all occurances of "flashplugin-installer" and "flashplugin-nonfree" from /var/lib/dpkg/status.
April 4, 2010
Flash problems after upgrading from Hardy to Lucid
I upgraded Ubuntu 8.04 (Hardy Heron) to 10.04 (Lucid Lynx) a few days ago. While it is still in "RC" stage, the graphical update-manager already offered me the upgrade. Which I did. I had to resolve to an ugly fix after the upgrade to get the proprietary Adobe Flash working. No matter what apt-get command I entered, there was this error message: