Sorry for the late replay/lack of information.

The forum in question is <http://forum.playredstone.com>.

I'm using the default settings provided by HTTrack, except for ignoring
robots.txt.

The issue is on the main page (and others), HTTrack will download it, and show
the links properly, and they link to other mirrored pages. But, when the
mirror goes deeper, such as into the topics, trying to access pages such as
the front Index again via the top breadcrumbs link results in a whole
different link being provided by HTTrack, which directs you to a page that
doesn't exist.

This issue isn't necessarily HTTrack's fault, but because the forums are
set-up to have links where one is simply "index.php", while another is
"index.php?act=idx" and another is "index.php?s=378433773".

Basically, is there any way I can set-up a wildcard or something along those
lines to alleviate this issue?
Sorry for any confusions/troubles.