It seems this plugin has compatibility issues with the Smart Archives Reloaded plugin.
When both plugins are activated and set up, the Archives, regardless of the plugin config, isn't displayed and a php error pops up (with debug set as "true"), which points toward the Groups plugin :
Notice: Undefined property: stdClass::$ID in /home/cilia.pro/www/wp-content/plugins/groups/lib/access/class-groups-post-access.php on line 89
Any hints as to how to fix this ?
nb : i'm also writing a post in the Smart Archives Reloaded support forum.