I recently tried installing Freenet on Tails .0.10.1, everything downloaded just fine, the installer even launched, but after running it I got a message saying "istallation failed!" what am I doing wrong?

No idea. We don't support installing other applications than the standard set included in Tails, especially not applications that are not packaged in Debian (like Freenet). You're on your own on this one.
Comment by Tails Mon 20 Feb 2012 10:08:40 AM CET