I know this is an older thread, but I wanted to clarify a couple of things in case someone floats in here from a search engine.
When manually installing a plugin, the actual folder structure will be /wp-content/plugins/ (no big, but it might confuse some people when they don't see the /wpcont/ folder).
Also (and this isn't a major issue), in order for the All in One
SEO Pack plugin to work properly, make sure the theme you select makes use of the wp_head() function. There are some themes out there, or custom built themes, which leave this out--some times on purpose and some times due to human error.
One other thing you should check for is that your theme doesn't already hardcode the head meta directly into the file. (i.e. add the
tag directly in the header.php file). If it does and you're using the plugin, you'll want to delete the hardcoded stuff.
So, in essence, double-check your blog's source code to make sure the plugin is working as intended and do some clean up if it's not.
~ Teli