I have created a simple website for my wife here... www.kristenmcashan.com using the thematic theme. Overall, I have made very few changes to it because things look great. However, recently I was working on the site and somehow killed the categories and archives functionality. Please view this category link here... http://kristenmcashan.com/category/accessorize-your-life/
As you can see there is not really anything going on. I cleared the theme and tried the default and categories seem to work fine. I also deleted the customized thematic theme and installed the default with NO changes and the categories pages are still not working. I'm not really an HTML/CSS guy but more just marketing so the nuts and bolts of theme changes are over my head.
ANY help or insight would be very appreciated!!!