I tried to use the netinst CD and I received the same error. http://cdimage.debian.org/debian-cd/4.0_r4a/i386/iso-cd/debian-40r4a-etchnhalf-i386-netinst.iso I tried also to remove the /target/var/cache/apt/archives/debconf_1.5.11etch2_all.deb file and let the system download it again, but this didn't solve the problem.