Hi Haochi,
Thanks for the link. This helped a lot. I posted a response there, but I’ll summarize it here:
After reading the post, I realized that this could be a problem with the .htaccess file. The .htaccess file had the wrong permissions (it was not writable) so WordPress could not update it. Wordtracker did however place the code it would have written to .htaccess in a text area at the bottom of my Permalink Settings page. I simply updated my .htaccess page manually by copying and pasting this code and changed the permissions to 777 so that WordPress will not have similar problems in the future.
The problem began for me when I changed the Permalink settings to “Day and Name.” This change would have been written to the .htaccess file but the file was not writable. So when WordPress went looking for my permalinks (Categories), I got a “page not found” error in my browser because it was looking for the links with a different URL. Now it’s working fine.
Thanks again,
Todd