You're not root. You should be using sudo before each command, or logged in as root.
On a side note, I have a serious problem: for some strange reason my /etc/apt folder now has a amd64 and a i386 folder, each with a copy of my sources.list. Debian devs seem to have changed something in the way on how libapt behaves (mixing repos for those archs that support it), but now it's broken.
This bug report seems to fit with some of my problems:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=534979
I'm messing with the apt conf right now, it is way too different of the one I was used to :P