Hi, unfortunately the solution in v2.7.1 did not work for me. The following change to osm.php did the trick:
-define('OSM_PRIV_WP_CONTENT_URL', site_url() . '/wp-content' );
-define('OSM_PRIV_WP_CONTENT_DIR', ABSPATH . 'wp-content' );
-define('OSM_PRIV_WP_PLUGIN_URL', OSM_PRIV_WP_CONTENT_URL. '/plugins' );
-define('OSM_PRIV_WP_PLUGIN_DIR', OSM_PRIV_WP_CONTENT_DIR . '/plugins' );
+define('OSM_PRIV_WP_PLUGIN_URL', plugins_url() );
+define('OSM_PRIV_WP_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );