Can you try the development version of the plugin? I’ve just fixed this.
Download it from http://ocaoimh.ie/y/2o
Just tried it on a dev site on the same server. It’s fixed the errors and I can activate/deactivate caching and delete the plugin again without any problems. So that looks like one issue down. FYI this is on a debian8/vestacp server if you need any specifics.
Similar issue on 1.6.2 I’m afraid.
Error: Your cache directory () did not exist and couldn’t be created by the web server. Check permissions.
Cannot continue… fix previous problems and retry.
Maybe delete your wp-content/wp-cache-config.php (or delete and install it again) and reconfigure the plugin again?