Strange apt-get error

[Chris Metcalf <chrismetcalf@gmail.com>]

I've been getting the strangest error from apt-get lately:

--------
root@fallenidol:/home/krezel# apt-get install ntop
Reading Package Lists... Done
Building Dependency Tree... Done
The following extra packages will be installed:
  libgdome2-0
The following NEW packages will be installed:
  libgdome2-0 ntop
0 upgraded, 2 newly installed, 0 to remove and 35 not upgraded.
Need to get 2493kB of archives.
After unpacking 6828kB of additional disk space will be used.
Do you want to continue? [Y/n]
WARNING: The following packages cannot be authenticated!
  libgdome2-0 ntop
Install these packages without verification? [y/N]
E: Some packages could not be authenticated
root@fallenidol:/home/krezel#
-------

My sources.list file:
-------
root@fallenidol:/home/krezel# cat /etc/apt/sources.list
# MPlayer
# deb http://marillat.free.fr/ unstable main
#deb ftp://ftp.nerim.net/debian-marillat/ unstable main

# Gnome Bluetooth
deb http://debian.usefulinc.com/gnome ./
deb-src http://debian.usefulinc.com/gnome ./

# Debian lines. Choose your mirror. http://www.debian.org/misc/README.mirrors
deb http://mirrors.kernel.org/debian/ unstable main
deb-src http://mirrors.kernel.org/debian/ unstable main
deb http://security.debian.org/ stable/updates main
-------

apt-get version:
-------
root@fallenidol:/home/krezel# apt-get --version
apt 0.6.25 for linux i386 compiled on Jun  9 2004 05:37:07
Supported Modules:
*Ver: Standard .deb
*Pkg:  Debian dpkg interface (Priority 30)
 S.L: 'deb' Standard Debian binary tree
 S.L: 'deb-src' Standard Debian source tree
 Idx: Debian Source Index
 Idx: Debian Package Index
 Idx: Debian dpkg status file

Installed packages of interest:
-------
root@fallenidol:/home/krezel# dpkg -l | grep apt
ii  apt            0.6.25         Advanced front-end for dpkg
ii  apt-file       2.0.3-7        APT package searching utility -- command-lin
ii  apt-listbugs   0.0.40         Lists critical bugs before each apt installa
ii  apt-show-versi 0.07           Lists available package versions with distri
ii  apt-spy        3.1-8          writes a sources.list file based on bandwidt
ii  apt-utils      0.6.25         APT utility programs
rc  apt-watch      0.3.1-2        Monitor apt sources for upgrades
rc  aptitude       0.2.14-3       curses-based apt frontend

root@fallenidol:/home/krezel# dpkg -l | grep dpkg
ii  alien          8.44           install non-native packages with dpkg
ii  apt            0.6.25         Advanced front-end for dpkg
ii  dlocate        0.5-0.1        fast alternative to dpkg -L and dpkg -S
ii  dpkg           1.10.23        Package maintenance system for Debian
ii  dpkg-dev       1.10.23        Package building tools for Debian

Help!!

Thanks,

-- 
Chris Metcalf
chris@chrismetcalf.net
http://chrismetcalf.net