This refers to /etc/apt/sources.list wc has your sarge site e.g.
deb
http://http.us.debian.org/debian/ sarge main contrib non-free
yours maybe different but principle same.
Change the end as above then apt-get update
then try what was suggested for azureus earlier with apt-get or synaptic or aptitude. Learn one method and know it then expand.
Good luck with debian.