New default starting-point in activ subj

Which ASP-page, code, and line number, do I have to modify, to make the dropdown menu, with the content: "Show Active Topics since" and "Show Topics", start at another date?

As it is now, it starts at the point, where the user last visited the forum.

I would like it to show the laste topics for ex. one month by default.

Can some one please help?

Thanks!

Regards,
KLR3