You are using a command for 11.10+ for 10.04. That might work but more than often does not.
Looking at the packages on ubuntu.com ppa-purge
can be found in lucid-backports
and not in lucid
: http://packages.ubuntu.com/lucid-backports/utils/ppa-purge So you need to add the backports to your sources. Please read the wiki page thoroughly. Enabling Backports Manually can be done by adding the following line to your /etc/apt/sources.list
deb http://archive.ubuntu.com/ubuntu lucid-backports main restricted universe multiverse
After that a (one time)
sudo apt-get update
sudo apt-get upgrade
should update your resource and the apt-get install ppa-purge
should work on your system too.