Unknown column source in migrating from Drupal 6 to Drupal 7

Same here

and here. any help would be appreciated.

Yes, a similar problem here too.
I never made a backup in 6 though, only Drupal 7.
The problem I have is that I cannot create a schedule, afther hitting the Save schedule button I get “An unknown error has occured” and in the logs I see a PDOException like the one mentioned above – but on the 'source_id' and not the 'source' column – and a bit longer:

PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'source_id' in 'field list': INSERT INTO {backup_migrate_schedules} (schedule_id, name, source_id, destination_id, profile_id, keep, period, last_run, enabled, cron) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9); Array ( [:db_insert_placeholder_0] => 08f800b5b22ef7d3fbcad79e6b70d83b [:db_insert_placeholder_1] => Dagelijks [:db_insert_placeholder_2] => db [:db_insert_placeholder_3] => scheduled [:db_insert_placeholder_4] => default [:db_insert_placeholder_5] => 14 [:db_insert_placeholder_6] => 86400 [:db_insert_placeholder_7] => 0 [:db_insert_placeholder_8] => 1 [:db_insert_placeholder_9] => 0 ) in drupal_write_record() (regel 6888 van /drupalpath/includes/common.inc).

Or does that make this a different issue?

A drupal 6 db is not compatible with drupal 7 so if you port from one to the other, you have to (at minimum) run update.php.

THANK YOU! i was trying the upgrade multiple times. never saw anything about running update.php, wow..