The zlib1.dll that is packaged with 3.42-2 (03/19/2008) is two years out of
date; the most recent version contains many bugfixes and several important
security fixes.

The current version can be obtained as a binary from the canonical source:

<http://www.zlib.net/>

I've found that this download is a drop-in replacement for the one that is
packaged with HTTrack.

Here is the MITRE writeup that indicates the vulnerable version of zlib1.dll:

<http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-1849>

Andrew