Yes, siteurl... (I'm on WP 1.2). (I'm the Anonymous.)
The style switcher uses a cookie to record your preferred style. My problem was that I was visiting the site as http://localhost/wp but the cookie was being written as to http://127.0.0.1/wp. As the script was reading the cookie from http://localhost/wp it couldn't detect the style change.
Can you provide a URL so I could check the problem? I looked at your site but it's using another style switcher (and it's working).