Group Details block enabled - fatal error

As soon as the Group Details block is enabled, got the following fatal error message when returning to any Group pages:

Error
The website encountered an unexpected error. Please try again later.
Error message

Notice: Undefined variable: role_rids in og_extras_preprocess_og_extras_group_info() (line 47 of /home/(my web site name removed here)/sites/all/modules/og_extras/theme/theme.inc).
Warning: Invalid argument supplied for foreach() in DatabaseCondition->compile() (line 1854 of /home/(my web site name removed here)/includes/database/query.inc).
PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 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 '))' at line 1: SELECT og_users_roles.uid AS uid FROM {og_users_roles} og_users_roles WHERE (gid = :db_condition_placeholder_0) AND (rid IN ()) ; Array ( [:db_condition_placeholder_0] => 75 ) in og_extras_get_users_by_roles() (line 77 of /home/(my web site name removed here)/sites/all/modules/og_extras/og_extras.module).