Membership not installing

So when I try to install the membership plugin, it seems to install however, the plugin does not seem to activate properly.

So, it does not appear in the sidebar, and it also seems to apply some kind of changes to the site and it seems to put everything into the protected mode.

When i uninstall it and delete the files, and then reinstall it, it just does the same thing.

So I am wondering if I remove the database tables too?

So which tables should i remove?