Alright, I used a bunch of different installing methods including some mentioned at the Author's plugin page.
Right now I have the plugin installed and managed to make it work albeit with mixed modifications and a problem.
At the plugin option page:
a) If i select a category, it changes even the post layout of my blog and just shows post titles from that category.
b) If I don't select a category, it appears to work, but once I get inside the blog entry, it DISPLAYS EACH AND EVERY BLOG ENTRY in full view (i,e the max amount of posts I've chosen to display on a page).
Am running WordPress 3.0.1 and Thesis Theme 1.7.