Hello,
When running cron, I get the following error:

Message PDOException : SQLSTATE[22007]: Invalid datetime format: 7 ERROR: invalid input syntax for type interval: "s.reminder_days_before DAYS" LINE 1: ...2-06-30 18:31:30' >= (field_date_value - INTERVAL 's.reminde... ^: SELECT n.title, n.nid, n.type, s.reminder_email, s.forwarding_email, field_date_value FROM {node} n INNER JOIN {signup} s ON s.nid = n.nid INNER JOIN {field_data_field_date} ON {field_data_field_date}.revision_id = n.vid WHERE (s.send_reminder = 1) AND (n.type = :type) AND ('2012-06-30 18:31:30' >= (field_date_value - INTERVAL 's.reminder_days_before DAYS')) AND ('2012-06-30 18:31:30' <= (field_date_value + INTERVAL '1 HOURS')); Array ( [:type] => evenement ) dans _signup_cron_send_reminders() (ligne 43 dans /home/oturpin/equidrup/sites/all/modules/signup/includes/cron.inc).

Any idea ?