function volunteer_cron() issue: unknown column 'start'

function volunteer_cron() issue.
I can't figure out what column you're meaning to query here. Should this be 'e.event_start'? Here's the details: every time cron.php (drupal 4.6.2) is called, I get the following two errors.
Unknown column 'start' in 'where clause' query: SELECT c.nid, c.cid FROM volunteer_contact_event c LEFT JOIN event e ON e.nid = c.nid WHERE start > 1120252205 AND start < 1120425005 AND c.stage = 3 in /mnt/newhome/vhosts/parentsright2know.chaosmt.net/htdocs/includes/database.mysql.inc on line 66.
and
Unknown column 'start' in 'where clause' query: SELECT c.nid, c.cid FROM volunteer_contact_event c LEFT JOIN event e ON e.nid = c.nid WHERE start < 1120252205 AND stage = 4 in /mnt/newhome/vhosts/parentsright2know.chaosmt.net/htdocs/includes/database.mysql.inc on line 66.
In the volunteer_contact_event table, I see the following columns:
cid int(10), rating int(2), comments text, nid int(10), stage int(2)
and in the event table, I see the following columns:
nid int(10), event_start int(10), event_end int(10), timezone varchar(100)
So, what's the right answer? where did I go wrong?