> I've noticed that if I change the password used for
> accessing a site that I've copied before and that
> I'm trying to update, all the old files are
> overwritten.

Yes.. because the URL has changed, and httrack sees the files are "new".

> I thought I might be able to manually edit the
> ht-cache files but the new.zip file has given me
> trouble.  When I try to uncompress it on a windows
> machine, winzip reports invalid filenames within the
> zip file.

The ZIP cache file is using very unusual filenames, and anyway is also using
ZIP meta-data (not preserved by most windows tools), so you won't be able to
edit anything with this method.

> Am I wasting my time?  Is there any way to preserve
> my old archived data after changing the password
> needed to access the website I'm trying to copy?
Err.. this will require some coding (using some ZIP library), and I'm not sure
whether it's worth making the effort (instead of redownloading the site).