I have 5 categories on my blog, all of them have been archived on the right column. I have one category called "ads", which is showing up just fine, http://obtv.wordpress.com/category/ads/
The problem i have with it though, is that i cannot get the older posts to show up when i click "older entries". When i do that, it simply directs me to http://obtv.wordpress.com/category/ads/page/2/ which is a blank page with no source codes. All other categories in my blog isn't affected by this and i can easily navigate through them via this method.
If anyone wants to know, i've set my blog to display 5 posts per page, and i have 9 posts in that category.