you have some lines in your /etc/apt/sources.list pointing to 'stable' instead of 'sarge' - on 08/04 stable=etch and ... boom!
/etc/apt/sources.list # deb file:///cdrom/ sarge main deb http://mirrors.kernel.org/debian/ stable main deb-src http://mirror.kernel.org/debian/ stable main deb http://security.debian.org/ stable/updates main #deb http://soulmachine.net/breezy/ unestable and more commented lines for testing main