When I create a sub-directory blog, the themes in the front end as well as the backend of the site do not work. In reviewing the css, it appears that if a sub-directory's address is "http://yoursite.com/subdomain/" it adds a /subdomain/ to every file it's looking for. ex" http://www.yoursite.com/subdomain/wp-content/themefolder/cssfile.css"
Do you know what could be causing this? I've deactivated all my plugins to see where it could have come from but no clue.