I think that bike comes stock with a cassette hub.
Same issue as a freewheel though, the hub is dragging too much, you need it to freewheel with very little drag in order to have the cranks not turn. If it is a freewheel then replace it and see how you make out, if it is a cassette hub it may be rebuildable, I am not familiar with that hub so can not comment on how hard that would be.