I have a query to pull all posts of a certain category. It

I have a query to pull all posts of a certain category. It used to work great but all of a suddenly stopped working. The only thing that has changed that I know of is the server has a newer version of php which I have no idea if that would break this. Here is what I had been using.

<?php query_posts(array('orderby' => 'DESC', 'cat' => 12,'showposts' => 12));

If I remove the 'cat' => 12 part I do get all posts. I assume my query is wrong but it is weird it used to work.

Can someone point me in the right direction?

Thanks!