It seems you don't have multiarch enabled. This could happen if you updated to Oneiric early in the dev cycle.
Please follow the instructions here to enable multiarch, and try again: https://lists.ubuntu.com/archives/ubuntu-devel- announce/2011-August/000886.html ** Changed in: flashplugin-nonfree (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/860141 Title: Cannot install flashplugin-installer due dependency problem To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/flashplugin-nonfree/+bug/860141/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs