The error seems to be in this SQL statement:
SELECT count(expert_id=? and event_date >= ? and expert_events_approved=1 and expert_events_deleted=
01782012-01-09) AS count_expert_id_and_event_date_and_expert_events_approved_1_and_expert_events_deleted_0_178_2012_01_09 FROM `events`
It complains about the "event_date >= ?" where of course the questionmark is wrong.
It looks like you do somehing on the line of
MyModel.where("event_date >= ?", @date_var)
(simplified)
But for some reason the questionmark is not replaced by the actual value.
Could you provide the actual Ruby code that is used to generate this query?