I'm having this problem too with CMS 6 r2 with some customers. It always comes in one minute intervals.
It is not Publishing versions job. If I change the publishing versions job interval to 5 minutes the error still repeats in every minute.
If I stop Scheduler, errors will stop too.
If I look properties of Scheduler service it says "EPiServer CMS 5 Scheduler Service". Maybe this is because of old Schedule version is not updated after EPiServer migration or something.