You may want to use Optware packages, due to fact the Debian version being old and out of date (lenny 0.7.9, optware 0.8.5).
Follow DebianOptware to get Optware installed and setup on Debian Lenny.
# /opt/bin/ipkg install rtorrent
This will update the package feeds, and then install rtorrent and the neccessary dependancies.
Due to the packages being optware packages, they are all located in /opt/bin, and configs in /opt/etc.
You then need to create a .rtorrent.rc config file in your home directory.
You should then be able to use the latest Optware rtorrent in Debian
To update and upgade later on:
# /opt/bin/ipkg update # /opt/bin/ipkg upgrade
Will update the package feed, and download any newer packages
If you would like to use a remote GUI, you can almost follow RtorrentWithRemoteGUI
However, you can install lighttpd from the Debian repositories - apt-get install lighttpd
This means it will configure it for debian, run it on startup and such
You can then follow the RtorrentWithRemoteGUI guide to edit your /etc/lighttpd/lighttpd.conf and your rtorrent conf
rtorrent can be run by using /opt/bin/rtorrent
Another way is InstallRtorrentOnDebain