When i run the "rvm install rbx-head" in my ubuntu 11.10.There seems to be some error in the installation errors as follows:
W: Failed to fetch http://ppa.launchpad.net/ferramroberto/filezilla/ubuntu/dists/oneiric/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/ferramroberto/filezilla/ubuntu/dists/oneiric/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
As i don't have more reputation, i was unable to post the error lines which contain links.