segfault from Malformed /etc/apt/sources.list

This is bad input, but it shouldn't segfault.

netboot install[1], preseed file[2] that adds some PPAs (one is broked) adds to
/target/etc/apt/sources.list

deb http://ppa.launchpad.net/intuitivenipple/video-editors/ubuntu

and causes

Oct 11 00:52:53 in-target: E: Malformed line 51 in source list /etc/apt/sources.list (dist)
Oct 11 00:52:53 kernel: [ 626.449950] aptitude[32144]: segfault at 8 ip 08141d01 sp bf8b8d10 error 4 in aptitude[8048000+206000]

[1] 32 and 64 netboot files from:
http://archive.ubuntu.com/ubuntu/dists/karmic/main/installer-i386/current/images/netboot/ubuntu-installer/i386/linux
http://archive.ubuntu.com/ubuntu/dists/karmic/main/installer-amd64/current/images/netboot/ubuntu-installer/amd64/linux

[2] preseed file is in attached tar, but the important part is:

d-i apt-setup/local0/repository string http://ppa.launchpad.net/intuitivenipple/video-editors/ubuntu

yes, missing the "karmic main" part.