"The plugin generated 296 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."
I tested this plugin for a client on his site (Thesis theme)and on one of my own sites afterwards (Twenty Eleven Parent theme). Both sites running WP 3.4.1 The # characters mentioned differed between sites.
Will try it again after the next update