I activated the plugin and there is no Custom Post Archives Settings in the dashboard. At the top of the Plugins page, the following message displays: "The plugin generated 318 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin." There are no other problems like "headers already sent" messages, though.
I deactivated all other plugins and still no Custom Post Archive settings in the dashboard.