I found strange thing with marketing campaign scheduling (i use latest 6.5.2 version). Scenario: create few contacts, add them to new list, create new marketing campaign for this list, set launch date in campaign screen. Everything works well. Campaign will be sent to contacts in specified time. But when i create another campaign with same list and set new launch date, it says that all emails already sent! But it's new campaign, absolutely different from first. So this campaign is never completed, it still Active=YES, and nothing happens when launch date comes.