In Ubuntu, uninstall your current flash plugin first. 

Then you will need to make sure that you have the alien and wget utilities installed for the script below to work. 

Then follow the steps of this script and do it manually or copy this script and do it automatically.

#!/bin/bash

# Get the file
wget http://fpdownload.macromedia.com/get/flashplayer/current/flash-plugin-9.0.31.0-release.i386.rpm

# Convert the file
sudo alien --scripts --to-deb flash-plugin-9.0.31.0-release.i386.rpm

# Install the file
sudo dpkg -i flash-plugin_9.0.31.0-1_i386.deb

# Run the post-install scripts
sudo /usr/lib/flash-plugin/homecleanup
sudo /usr/lib/flash-plugin/setup

# Restart web browser reminder
echo "Restart your web browser to enable the Flash plugin"