Get error in error log related to prosites plugin

I get this error in error log.
[21-Feb-2014 15:34:26 UTC] WordPress database error Multiple primary key defined for query ALTER TABLE wp_supporter_ads ADD PRIMARY KEY (supporter_ads_ID) made by require_once('wp-admin/network/admin.php'), require_once('wp-admin/admin.php'), require_once('wp-load.php'), require_once('wp-config.php'), require_once('wp-settings.php'), do_action('plugins_loaded'), call_user_func_array, ProSites_PluginLoader->load_modules, ProSites_Module_Ads->__construct, ProSites_Module_Ads->install, dbDelta