You have to analyze what the program is downloading and why. If the links are
active links which change their address every time called upon, Httrack might
consider these as "new" links and download them too.

You have to spend a little effort to learning first how the website is
organized in order to be able to capture it well. Put the logging options on
and analyze the logs, see what is getting downloaded.

With the minimal information you gave no other advice is really possible. Tell
what site, what pages etc and maybe someone will have a look.