I get this error message, when I try to Enable 'Event Reminder' on Notifications settings / Subscription / Configure.

Event Reminder never gets on. Always stays checked off. So my event reminders never go out.

warning: Illegal offset type in isset or empty in XXX/sites/all/modules/notifications/notifications.module on line 612.
warning: Illegal offset type in isset or empty in XXX/sites/all/modules/notifications/notifications.module on line 612.

CCK Signup 6.x-1.0-beta2
CCK Sign-up notifications 6.x-1.0-beta2
Notifications 6.x-4.0-beta7

I have no idea which module this error belongs to.