hi, about this:

If your blog is installed in the root, “/”, of your domain you can add this one line to stop the 404 requests generated:

RewriteRule ^(.*)/wp-comments-post.php – [F,L]

what if I installed into a subdirectory, i.e. wordpress ?

same issue here:

Check your browser for the cookie it leaves and use the following code to block almost all of your comment spam:

RewriteCond %{HTTP_COOKIE} !^.*put_cookie_value_here.*$
RewriteRule ^wp-comments-post.php – [F,L]

do I need to change the path, and if yes, how?

And how do I know which one is the cookie set by your cookie plugin?