Do it the old fashioned way. Edit /etc/apt/sources.list...
deb http://us.archive.trisquel.info/trisquel/ belenos main deb-src http://us.archive.trisquel.info/trisquel/ belenos main deb http://us.archive.trisquel.info/trisquel/ belenos-updates main deb-src http://us.archive.trisquel.info/trisquel/ belenos-updates main deb http://us.archive.trisquel.info/trisquel/ belenos-security main deb-src http://us.archive.trisquel.info/trisquel/ belenos-security main sudo aptitude update sudo aptitude full-upgrade
