First, open up a Terminal window (howto located here: http://www.psychocats.net/ubuntu/terminal)
Then type in it:
sudo bash /usr/lib/te/uninstall.sh
Follow the instructions.
Then once it is finished, type in:
cd
sudo dpkg -l te && sudo dpkg -r te
[ -d /usr/lib/te ] && sudo rm -rf /usr/lib/te
Then re-download from: https://sourceforge.net/projects/tenhancements/files
Read the README.
Follow the instructions.
Then restart your Terminal.
Then you should be able to finally use TE!
Troubleshooting:
If all of the above didn't have any problems, but after you restart your Terminal, you cannot type in any TE commands, try typing this in the Terminal window:
source ~/.profile
source /etc/profile
Then try a command such as:
techeck && echo 'It works!'
