When I log in with an admin account, I have the Favorites menu with the new "Delete Cache" link added in the last release 0.8.8
When I log in with an non admin account, I have no Favorites actions in the header but I can read a warning message :
Warning: Invalid argument supplied for foreach() in [...]/wp-admin/includes/template.php on line 3172
If I comment the line 1284 below :
add_filter( 'favorite_actions', 'wp_cache_favorite_action' );
in the file './plugins/wp-super-cache/wp-cache.php'
Warning message disappears for non admin user.
Do you have the same behaviour on your wordpress with the release 0.8.8 ?