how jforum does redirect to error page

[Migrated From Jforum.net]

Hello All,

I make make a new page in jforum, which show only the category name in the forum index.
If we click the category name, it will bring us to page where it shows the forums for that category
the link is like this http://hanapewee.com/jforum/forums/bycategory/1.page
1 = category_id
but when I change "1" with other category_id whose user doesn't have permission to view.. it shows me error page, not the page with the message "opps.. you're not allowed to se this page" or something.

What should I do to make it redirect to that "oops" page?

Thanks

-hanapewee-
[originally posted on jforum.net by hanapewee]