[Plugin: WP Sentry] Error

Hi…
what should i do…
had this error when opening a group page:

Fehler beim Verarbeiten des Skript-Headers / Error parsing script headers:

WordPress-Datenbank-Fehler You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' member_of)' at line 1 für Abfrage SELECT id FROM wp_sentry_groups WHERE FIND_IN_SET(, member_of) von require, require_once, include, get_sidebar, locate_template, load_template, require_once, dynamic_sidebar, call_user_func_array, MultiWidget->widget_callback, AuthorAvatarsWidget->widget, UserList->output, UserList->get_output, UserList->get_users, UserList->_filter, UserList->get_user_postcount, get_usernumposts, get_private_posts_cap_sql, current_user_can, call_user_func_array, WP_User->has_cap, apply_filters, call_user_func_array, wp_sentry->has_capability, wp_sentry->user_is_allowed

Skript-Ausgabe (111782 Bytes) folgt / Script output (111782 bytes) follows:
WordPress-Datenbank-Fehler You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' member_of)' at line 1 für Abfrage SELECT id FROM wp_sentry_groups WHERE FIND_IN_SET(, member_of) von require, require_once, include, get_sidebar, locate_template, load_template, require_once, dynamic_sidebar, call_user_func_array, MultiWidget->widget_callback, AuthorAvatarsWidget->widget, UserList->output, UserList->get_output, UserList->get_users, UserList->_filter, UserList->get_user_postcount, get_usernumposts, get_private_posts_cap_sql, current_user_can, call_user_func_array, WP_User->has_cap, apply_filters, call_user_func_array, wp_sentry->has_capability, wp_sentry->user_is_allowed