Romove category conflict with pagination

Hello there,

I wanted to remove a category from the loop of the homepage using this code:

‘<?php query_posts($query_string . ‘&cat=-171′); ?>’

where 171 is obviously the number of the category i want to remove.

This code works, i mean, in the homepage that category is not displayed as it should be. The problem is that if i want to press “next page” or others commands regardind the page navigation, just doesn’t work.
Also the archives and all the funcion referring the categorization of the article doesn’t work now.

There is someone could help me in this?

my site http://www.mktrsclub.com/