package flashplugin-installer 10.3.183.7ubuntu0.11.04.1 failed to install/upgrade: subproces installed post-installation script gaf een foutwaarde 2 terug

Check your filesystem with smartctl:
https://help.ubuntu.com/community/Smartmontools

And then with fsck:
http://www.howforge.com/how-force-fsck-ubuntu

That way, if there is an underlying problem with your filesystem, it may be fixed.

Then completely remove and reinstall the Flash plugin, by running these commands in the Terminal (press Ctrl+Alt+T to open a Terminal window, then paste these commands into the Terminal to run them):

sudo apt-get purge adobe-flashplugin
sudo apt-get purge flashplugin-installer flashplugin-nonfree
sudo apt-get install flashplugin-installer

You may be prompted for your password. As you enter it, you won't see any placeholder characters (like *). That's OK. Also, don't worry if the first of those three commands fails with an error message saying that it cannot find adobe-flashplugin.

After you have run those commands, then close out of all web browser windows (if you had not done so already), and then go back into a browser and see if Flash works. If it works, you can mark this question as Solved. If it does not, then please post a reply with all the text from the Terminal (in the Terminal, run Edit > Select All followed by Edit > Copy, then paste here). If you don't know what Flash is and thus need an explanation for how to see if it works: go to a site that uses Flash, such as YouTube!, and see if animated Flash content (in the case of YouTube!, embedded videos) are able to play without problems. (Please note that *not* all embedded videos on the web use Flash.)