I had this working in a test cart on 1.3.8a but after simply moving the test folders into the live site and changing the configure files, the site's working fine but I no longer see Simple Seo under the Configuration menu to be able to turn the mod on. I DO see it under Extras.

I've reinstalled, checked my permissions on the cache, made sure my .htaccess file reads correctly, and even run /ssu_check.php. I have Module Mangager installed as well.

Any ideas?