Well I think the reason for the timeslot shift is pretty clear for next week. Both Australia's Got Talent and TARAus are moving to Thursday night, while Wednesday night has a movie (Evan Almighty) because next Wednesday night is Game II of the 2012 State of Origin Series, airing on Channel Nine, so if TARAus airs against it, ratings would severely drop for next week's episode, so the move to Thursday is a smart one.
I speculate that this will be a temporary swap and that TARAus will be back to Wednesday in a fortnight, but if TARAus does return to Wednesday, then I speculate Episode 6 will also shift to Thursday, to avoid clashing with Game III of the State of Origin.