Tor Blocker stands for limiting actions to the users that came from Tor exit nodes.
For any problem you face with the plugin activation, please visit support forums or contact us at firstname.lastname@example.org.
Yes, this plugin works really fine with WordPress 3.8.1! It should also work with earlier versions, but the testing was done at the latest stable version and that is 3.8.1, so you always should run the latest WordPress version to escape possible problems.
No worries. The tor exit list is updated frequently each 5 minutes or 5 hours, depending on which version is used, so users using tor that are not on the list will be updated after this amount of time and thus will be denied by the plugin.
Yes. Every time the plugin is activated its options are set to default values, so it means you have to set them up again.
No limit at all. You can put as many parameters in the textarea as you want. The plugin will recognize any request parameter in the URL and stop the user immediately.
By default, tor users are allowed just to visit the site and read its public content. As you might guess, you can deny this too, so the tor user is stopped before reaching your site.